Initial Commit - days 01-12

day10/ex1-c.c

@@ -0,0 +1,132 @@
+/* ex1-c: Advent2020 game, day 10/game 1
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+struct list {
+    unsigned size;
+    unsigned last;
+    unsigned long long *list;
+};
+
+#define DEFNSUM		25
+#define BLOCKSIZE	1024    /* number of elements for realloc() */
+
+void merge(array, left, mid, right)
+    unsigned long long *array;
+    int left, mid, right;
+{
+    unsigned long long temp[right-left+1];
+    int pos=0, lpos = left, rpos = mid + 1, iter;
+    while(lpos <= mid && rpos <= right) {
+        if(array[lpos] < array[rpos]) {
+            temp[pos++] = array[lpos++];
+        }
+        else {
+            temp[pos++] = array[rpos++];
+        }
+    }
+    while(lpos <= mid)  temp[pos++] = array[lpos++];
+    while(rpos <= right)temp[pos++] = array[rpos++];
+    for(iter = 0;iter < pos; iter++) {
+        array[iter+left] = temp[iter];
+    }
+    return;
+}
+
+void mergesort(array, left, right)
+    unsigned long long *array;
+    int left, right;
+{
+    int mid = (left+right)/2;
+    if(left<right) {
+        mergesort(array, left, mid);
+        mergesort(array, mid+1,right);
+        merge(array, left, mid, right);
+    }
+}
+
+void print_list(list)
+    struct list *list;
+{
+    unsigned i, psize=list->last;
+    unsigned long long *ptr=list->list;
+
+    fprintf(stderr, "LIST: address=%p pinstr=%p size=%d\n", list, ptr, psize);
+    for (i=0; i<psize; ++i)
+        printf("[%u] %llu\n", i, *(ptr+i));
+}
+
+static struct list *add_val(list, val)
+    struct list *list;
+    unsigned long long val;
+{
+    //int val;
+    unsigned cur, size;
+    unsigned long long *ptr;
+
+    if (!list) {
+        list=malloc(sizeof(struct list));
+        list->list=malloc(sizeof(unsigned long long)*BLOCKSIZE);
+        list->size=BLOCKSIZE;
+        list->last=0;
+    }
+    cur=list->last;
+    size=list->size;
+
+    if (cur == size) {
+        size+=BLOCKSIZE;
+        list->size=size;
+        list->list=realloc(list->list, sizeof(unsigned long long)*size);
+        fprintf(stderr, "realloc buf: cur=%d size=%d ptr=%p\n", cur, size, list->list);
+    }
+    ptr=list->list+cur;
+
+    //sscanf(line, "%d", &val);
+    *ptr=val;
+    list->last++;
+
+    return list;
+}
+
+unsigned *calc(list)
+    struct list *list;
+{
+    static unsigned res[4];
+    unsigned long long *ptr=list->list;
+    unsigned last=list->last, i;
+
+    for (i=0; i<4; ++i)
+        res[i]=0;
+    for (i=1; i<last; ++i) {
+        unsigned prev=ptr[i-1], cur=ptr[i];
+        res[cur-prev]++;
+    }
+    return res;
+}
+
+int main(ac, av)
+    int ac;
+    char **av;
+{
+    char line[80];
+    struct list *list=NULL;
+    unsigned long long res, last;
+    unsigned *result;
+
+    list=add_val(list, 0);
+    while (fgets(line, sizeof line, stdin)) {
+        sscanf(line, "%llu", &res);
+        list=add_val(list, res);
+    }
+    mergesort(list->list, 0, list->last-1);
+    last=list->list[list->last-1];
+    list=add_val(list, last+3);
+    //print_list(list);
+    result=calc(list);
+    printf("%s : diff1=%u diff2=%u res=%u\n", *av, result[1], result[3],
+           result[1]*result[3]);
+    exit (0);
+}