commit 0b6c839b4df50bd76d7cc341c0e650edbcfe5e77
Author: Bruno Raoult <braoult@gmail.com>
Date:   Wed Jan 20 16:22:59 2021 +0100

    initial version

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..4b06518
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,9 @@
+core
+com*
+ex1*
+*.o
+perm*
+oper
+tree
+lceb
+gmon.out
\ No newline at end of file
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..e8895fb
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,28 @@
+SHELL := /bin/bash
+#CFLAGS := -w -O3
+CFLAGS := -w -g -pg -DDEBUG
+TIME := \time -f "\ttime: %E real, %U user, %S sys\n\tcontext-switch:\t%c+%w, page-faults: %F+%R\n"
+export PATH := .:$(PATH)
+
+TARGETS=lceb tree oper stack eval
+INCLUDES=lceb.h
+OBJS=$(TARGETS:=.o)
+
+.PHONY: all clean stack eval
+
+all: $(TARGETS)
+
+lceb: $(OBJS)
+
+tree: tree.c lceb.h
+	$(CC) $(CFLAGS) -DSTANDALONE -o $@ $?
+oper: oper.c lceb.h
+	$(CC) $(CFLAGS) -DSTANDALONE -o $@ $?
+
+ex2: ex2-c
+	@$(TIME) ex2-c < $(INPUT)
+
+%.o: %.c $(INCLUDES)
+
+clean:
+	rm -f $(TARGETS) $(OBJS) core
diff --git a/eval.c b/eval.c
new file mode 100644
index 0000000..7dbb53f
--- /dev/null
+++ b/eval.c
@@ -0,0 +1,62 @@
+#include <stdio.h>
+#include "lceb.h"
+
+int eval_cell(pos)
+    STACKELT *pos;
+{
+    STACKELT *prev=pos-1;
+    int curop=pos->curop, nop=pos->nop;
+    int val1, val2;
+    char op;
+    int res;
+
+    while (curop<nop) {
+        op=pos->op[curop];
+        val2=pos->val;
+        res=-1;
+        printf("eval_cell(%c, %d)\n", op, val2);
+        while ((val1=prev->val) == -1)
+            prev--;
+        switch (op) {
+            case Nop:
+            case End:
+                return val2;
+                break;
+            case Add:
+                res=val1+val2;
+                break;
+            case Mul:
+                res=val1*val2;
+                break;
+            case Sub:
+                if (val1 > val2)
+                    res=val1-val2;
+                break;
+            case Div:
+                if (val1 > val2 && (val1 % val2 == 0))
+                    res=val1/val2;
+                break;
+        }
+        curop++;
+        if (res==-1)
+            break;
+        pos->val=res;
+        printf("\t--> eval=%d\n", res);
+    }
+    return res;
+}
+
+int eval_stack(stack)
+    STACK *stack;
+{
+    int pos, last=stack->last, res;
+    STACKELT *pstack=stack->stack;
+
+    printf("+++++ eval_stack: addr=%p\n", pstack);
+    for (pos=1; pos<last; ++pos) {
+        //printf("eval_stack(%d/%d): addr=%p\n", pos, stack->last, pstack+pos);
+        res=eval_cell(stack->stack+pos);
+        //printf("  -> val(%d)=%d\n", pos, res);
+    }
+    return res;
+}
diff --git a/lceb.c b/lceb.c
new file mode 100644
index 0000000..a9bcd32
--- /dev/null
+++ b/lceb.c
@@ -0,0 +1,68 @@
+/* compte-est-bon.c - should one day solve this game...
+ *
+ *   $ make compte-est-bon
+ *   $ ./compte-est-bon target n1 n2 [...n6]
+ *
+ * At least 2 "n" are mandatory, and no more than 6 are allowed.
+ *
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdarg.h>
+#include <malloc.h>
+#include <string.h>
+#include "lceb.h"
+
+
+
+int main(ac, av)
+    int ac;
+    char **av;
+{
+    unsigned target;
+    STACK *stack;
+    int i, stacksize, val, res;
+    char *ops="+-*/", *opscomb;
+    int len_ops=strlen(ops), ncombs, nops;
+
+    if (ac < 4 || ac > 2+MAXINPUT) {
+        fprintf(stderr, "usage: %s target n1 n2 [...n%d]\n", *av, MAXINPUT);
+        exit(1);
+    }
+    target=atoi(av[1]);
+    stacksize=2*(ac-2)-1;
+    nops=ac-2-1;
+    ncombs=ncombinations(len_ops, nops);
+    printf("target=%d\nstacksize=%d\nops_comb=%d\n", target, stacksize, ncombs);
+    printf("len_ops=%d\nnops=%d\nops_comb=%d\n", len_ops, nops, ncombs);
+    stack=new_stack(stacksize, "Main Stack");
+    for (i=2; i<ac; ++i) {
+        val=atoi(av[i]);
+        push_stack(stack, Nop, val);
+    }
+
+    print_stack(stack, 1);
+    printf("sorting stack...\n");
+    mergesort_stack(stack->stack, 0, stack->last-1);
+    print_stack(stack, 1);
+
+    i=1;
+    do {
+        printf("permutation %2d: ", i++);
+        print_stack(stack, 0);
+    } while (permute_stack(stack->stack, stack->last));
+
+    printf("operators combinations (%d) = ", ncombs);
+    for (i=0; i<ncombs; ++i) {
+        opscomb=combination(ops, nops, i);
+        //printf("OPS=%s\n", opscomb);
+        //set_ops_stack(stack, opscomb);
+        //print_stack(stack, 0);
+        //res=eval_stack(stack);
+        //printf("EVAL=%d\n", res);
+    }
+    printf("\n");
+
+    exit(0);
+}
diff --git a/lceb.h b/lceb.h
new file mode 100644
index 0000000..32d3b82
--- /dev/null
+++ b/lceb.h
@@ -0,0 +1,52 @@
+
+#define MAXINPUT        6                         /* max numbers as input */
+#define ALLOCSIZE       1024                      /* # of elements to alloc when needed */
+#define EMPTY           -1
+
+typedef enum {
+    Nop='N',
+    Add='+',
+    Sub='-',
+    Mul='x',
+    Div='/',
+    End='\0'                                      /* Only for "printf" */
+} OPER;
+
+typedef struct stackelt {
+    int val;
+    int nop;                                      /* number of operators */
+    int curop;                                    /* current operator */
+    char op[MAXINPUT];                            /* MAXINPUT-1 + ending \0 */
+    int next, prev;                               /* for eval: avoids restructuring stack */
+} STACKELT;
+
+typedef struct stack {
+    char name[80];
+    int size;
+    int last;
+    int eval;
+    STACKELT *stack;
+} STACK;
+
+/* tree.c */
+extern void gen_tree(int *seq, int n, int nb1, int nb0);
+
+/* stack.c */
+extern void print_stack(STACK *stack, int details);
+extern STACK *new_stack(int size, char *name);
+extern STACKELT *push_stack(STACK *stack, OPER op, int val);
+extern STACKELT *pop_stack(STACK *stack);
+extern STACK *dup_stack(STACK *stack, char *name);
+extern void swap_stack(STACKELT *elts, int i, int j);
+extern int permute_stack(STACKELT *array, int n);
+extern void mergesort_stack(STACKELT *array, int left, int right);
+extern STACKELT *set_op_stack(STACK *stack, int pos, OPER op);
+extern STACKELT *set_ops_stack(STACK *stack, char *ops);
+
+/* oper.c */
+extern unsigned ncombinations(int nops, int len);
+extern char *combination(char *ops, int len, int n);
+
+/* eval.c */
+extern int eval_cell(STACKELT *pos);
+extern int eval_stack(STACK *stack);
diff --git a/oper.c b/oper.c
new file mode 100644
index 0000000..392d44e
--- /dev/null
+++ b/oper.c
@@ -0,0 +1,58 @@
+#include <string.h>
+#include <malloc.h>
+#include "lceb.h"
+
+unsigned ncombinations(nops, len)
+    int nops, len;
+{
+    int result = 1;
+    while(len > 0){
+        if(len & 1)
+            result *= nops;
+        nops *= nops;
+        len >>=1;
+    }
+    return result;
+}
+
+char *combination(ops, len, n)
+    char *ops;                                    /* string to combine */
+    int len;                                      /* len of result */
+    int n;                                        /* iteration # */
+{
+    static char *res=NULL;
+    static int len_ops;
+    int i;
+
+    if (!res) {                                   // 1st call
+        len_ops=strlen(ops);
+        res=malloc(len * sizeof(char) + 1);
+    }
+    for(i=0; i<len; ++i){
+        res[len -i -1] = ops[n % len_ops];
+        n /= len_ops;
+    }
+    return res;
+}
+
+#ifdef STANDALONE
+int main(ac, av)
+    int ac;
+    char **av;
+{
+    char *ops="+-*/", *p;
+    int len_ops=strlen(ops);
+    int i, j, nops, ncombs;
+
+    nops=atoi(*(av+1));
+    ncombs=ncombinations(len_ops, nops);
+    printf("# operators combinations : %d\nlist = ", ncombs);
+    for (i=0; i<ncombs; ++i) {
+        p=combination(ops, nops, i);
+        printf("[%s]\n", p);
+        //for (j=0; j<4; ++j)
+        //    distribute(j, p);
+        //printf("\n");
+    }
+}
+#endif
diff --git a/stack.c b/stack.c
new file mode 100644
index 0000000..70b0349
--- /dev/null
+++ b/stack.c
@@ -0,0 +1,212 @@
+#include <stdio.h>
+#include <malloc.h>
+#include <string.h>
+#include "lceb.h"
+
+void print_stack(stack, details)
+    STACK *stack;
+    int details;
+{
+    int i;
+
+    if (details) {
+        printf("Stack [%s] dump: %d/%d used\n", stack->name, stack->last, stack->size);
+        printf("\tValue: %4d\n", stack->eval);
+        for (i=0; i<stack->last; ++i)
+            printf("\t%02d: Op=%s Val=%4d\n",
+                   i, (char *)stack->stack[i].op, stack->stack[i].val);
+    } else {
+        printf("Stack [%s] : ", stack->name);
+        for (i=0; i<stack->last; ++i) {
+            printf("%d[%s] ", stack->stack[i].val, (char *)stack->stack[i].op);
+        }
+        printf("\n");
+    }
+}
+
+STACK *new_stack(size, name)
+    int size;                                     /* 0 if empty */
+    char *name;
+{
+    STACK *stack;
+    STACKELT *pelt;
+    int i;
+
+    stack=malloc(sizeof (STACK));
+    stack->stack=NULL;
+    stack->size=0;
+    stack->last=0;
+    stack->eval=0;
+    strncpy(stack->name, name? name: "No name", sizeof(stack->name));
+    if (size) {
+        pelt=malloc(size*sizeof(STACKELT));
+        stack->size=size;
+        stack->stack=pelt;
+        for (i=0; i<size; ++i) {
+            (pelt+i)->nop=0;
+            (pelt+i)->curop=0;
+            (pelt+i)->op[0]=End;
+            (pelt+i)->val=-1;
+            (pelt+i)->next=i+1;
+            (pelt+i+1)->prev=i;
+        }
+        (pelt+i-1)->next=-1;
+    }
+    return stack;
+}
+
+STACKELT *push_stack(stack, op, val)
+    STACK *stack;
+    OPER op;
+    int val;
+{
+    int pos=stack->last;
+    int size=stack->size;
+    STACKELT *pelt=stack->stack+stack->last;
+
+    if (pos >= size) {
+        fprintf(stderr, "stack overflow: size=%d last=%d\n", size, pos);
+        return NULL;
+    }
+    pelt->nop=0;
+    pelt->curop=0;
+    //pelt->op[0]=op;
+    pelt->val=val;
+    stack->last++;
+    return pelt;
+}
+
+STACKELT *pop_stack(stack)
+    STACK *stack;
+{
+    int pos=stack->last+1;
+    int size=stack->size;
+    STACKELT *pelt=stack->stack+stack->last;
+
+    if (pos==0) {
+        fprintf(stderr, "stack empty: size=%d last=%d\n", size, pos);
+        return NULL;
+    }
+    stack->last--;
+    return pelt;
+}
+
+STACK *dup_stack(stack, name)
+    STACK *stack;
+    char *name;
+{
+    STACK *new;
+    STACKELT *src=stack->stack, *dst;
+    int size=stack->size, last=stack->last, i;
+
+    new=new_stack(size, name);
+    dst=new->stack;
+    for (i=0; i<last; ++i) {
+        dst->nop=src->nop;
+        dst->curop=src->curop;
+        dst->val=src->val;
+        memcpy(dst->op, src->op, sizeof(src->op));
+    }
+    stack->last++;
+    return new;
+}
+
+void swap(elts, i, j)
+    STACKELT *elts;
+    int i, j;
+{
+    STACKELT tmp=elts[i];
+    elts[i] = elts[j];
+    elts[j] = tmp;
+}
+
+int permute_stack(array, n)
+    STACKELT *array;
+    int n;
+{
+    int i, j, start, end;
+
+    for(i=n-2; i>-1; i--) {
+        if(array[i+1].val > array[i].val) {
+            for(j=n-1; j>i; j--){
+                if(array[j].val > array[i].val){
+                    // swap
+                    swap(array, i, j);
+                    // reverse
+                    for (start=i+1, end=n-1; start < end; ++start, --end)
+                        swap(array, start, end);
+                    return 1;
+                }
+            }
+        }
+    }
+    return 0;
+}
+
+
+void mergesort_stack(array, left, right)
+    STACKELT *array;
+    int left, right;
+{
+    int mid = (left+right)/2;
+    int pos=0, l=left, r=mid+1, i;
+    STACKELT tmp[right-left+1];
+
+    if(left < right) {
+        mergesort_stack(array, left, mid);
+        mergesort_stack(array, mid+1,right);
+        while (l <= mid && r <= right) {
+            if (array[l].val < array[r].val) {
+                tmp[pos++] = array[l++];
+            }
+            else {
+                tmp[pos++] = array[r++];
+            }
+        }
+        while (l <= mid)
+            tmp[pos++] = array[l++];
+        while (r <= right)
+            tmp[pos++] = array[r++];
+        for (i = 0; i < pos; ++i)
+            array[i+left] = tmp[i];
+    }
+}
+
+STACKELT *set_op_stack(stack, pos, op)
+    STACK *stack;
+    int pos;
+    OPER op;
+{
+    int size=stack->size;
+    STACKELT *pelt=stack->stack+pos;
+
+    if (pos >= size) {
+        fprintf(stderr, "set_op: stack overflow: size=%d last=%d\n", size, pos);
+        return NULL;
+    }
+    pelt->op[pelt->nop++]=op;
+    pelt->op[pelt->nop]=End;
+    //pelt->val=val;
+    //stack->last++;
+    return pelt;
+}
+
+STACKELT *set_ops_stack(stack, ops)
+    STACK *stack;
+    char *ops;
+{
+    //int size=stack->size;
+    int last=stack->last;
+    int i, j;                                     /* 1st operator in on second number */
+    STACKELT *pelt=stack->stack;
+
+    printf("setting ops [%s]\n", (char *)ops);
+    for (i=1, j=0; i<last; ++i, ++j) {
+        pelt[i].nop=1;
+        pelt[i].curop=0;
+        printf("setting op [%c-%x] to pos %d[%d]\n", ops[j], ops[j], i, pelt[i].nop);
+        pelt[i].op[0]=ops[j];
+        pelt[i].op[1]=End;
+    }
+    return pelt;
+}
diff --git a/tree.c b/tree.c
new file mode 100644
index 0000000..aad074f
--- /dev/null
+++ b/tree.c
@@ -0,0 +1,45 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <malloc.h>
+#include "lceb.h"
+
+void gen_tree(seq, n, nb1, nb0)
+    int *seq;
+    int n;                      /* number of nodes */
+    int nb1;                    /* number of "1" */
+    int nb0;                    /* number of "0" */
+{
+    int i;
+
+     if((nb1 + nb0) == 2*n) {   /* end */
+        seq[2*n] = 0;
+        printf("tree=");
+        for (i=0; i<=2*n; ++i)
+            printf("%d", seq[i]);
+        putchar('\n');
+        return;
+     }
+
+    if(nb1 >= nb0 && nb1 < n) {
+        seq[nb1+nb0] = 1;
+        gen_tree(seq, n, nb1+1, nb0);
+    }
+
+    if(nb0 < nb1 && nb1 <=n) {
+        seq[nb1+nb0] = 0;
+        gen_tree(seq, n, nb1, nb0+1);
+    }
+}
+
+#ifdef STANDALONE
+main(ac, av)
+    int ac;
+    char **av;
+{
+    int n;
+    int array[1024];
+    n=atoi(av[1]);
+    gen_tree(array, n, 0, 0);
+    exit(0);
+}
+#endif