initial commit

bash/tournament/tournament.sh

@@ -0,0 +1,132 @@
+#!/usr/bin/env bash
+# v1:   - initial version
+# v2-3: - backport bubble sort (while -> for) & debug system from next exercises
+#       - always read from stdin
+#       - some syntax improvement
+# v4:   - cosmetic/syntax changes
+#       - change from empty file handling (empty string becomes valid filename)
+# v5:   - cosmetic changes following "shellcheck" usage.
+# v6:   - removed debug calls.
+# v7-8: - cosmetic changes
+
+die() {
+    echo "${@}" >&2
+    exit 1
+}
+
+# the results, associative arrays with team name as key. Some tables look
+# redundant, but easier to understand.
+declare -A mp                                               # matches played
+declare -A win                                              # matches won
+declare -A draw                                             # matches tied
+declare -A loss                                             # matches lost
+declare -A points                                           # points
+declare -a order                                            # final order.
+
+nteams=0
+
+# create a team entry in arrays if non existent. $1: team
+create_team() {
+    if ! [[ -v "mp[$1]" ]]; then
+        (( nteams++ ))
+        (( mp["$1"]=0 ))
+        (( win["$1"]=0 ))
+        (( loss["$1"]=0 ))
+        (( draw["$1"]=0 ))
+        (( points["$1"]=0 ))
+        order[$nteams]="$1"
+    fi
+}
+
+# update results for a team: $1, $2: teams, $3: result for $1: win/draw/loss
+update_results() {
+    create_team "$1"
+    create_team "$2"
+
+    ((mp["$1"]++))
+    ((mp["$2"]++))
+    case "$3" in
+        win)
+            ((win["$1"]++))
+            ((loss["$2"]++))
+            ((points["$1"]+=3))
+            ;;
+        loss)
+            ((win["$2"]++))
+            ((loss["$1"]++))
+            ((points["$2"]+=3))
+            ;;
+        draw)
+            ((draw["$1"]++))
+            ((draw["$2"]++))
+            ((points["$1"]++))
+            ((points["$2"]++))
+            ;;
+        *)                                        # should not happen
+            die "fatal: invalid result $3, exiting."
+    esac
+}
+
+# inspired from https://stackoverflow.com/questions/7442417/how-to-sort-an-array-in-bash
+# (bubble sort)
+sort_teams()
+{
+    local max i
+
+    for ((max=nteams; max>0; max--)); do
+        for ((i=1; i<max; ++i )); do
+            local team1=${order[$i]} team2=${order[$i + 1]} switch=0
+
+            if (( ${points["$team1"]} < ${points["$team2"]} )) || \
+                   ( (( ${points["$team1"]} == ${points["$team2"]} )) && \
+                         [[ "$team1" > "$team2" ]] ); then
+                order[$i]="$team2"
+                order[$i + 1]="$team1"
+            fi
+        done
+    done
+}
+
+output() {
+    printf "%-30s |%3s |%3s |%3s |%3s |%3s\n" "${@:1:6}"
+}
+
+output_team() {
+    output "$1" "${mp[$1]}" "${win[$1]}" "${draw[$1]}" "${loss[$1]}" "${points[$1]}"
+}
+
+# output teams, according to "order" table
+output_teams() {
+    local i
+    # header
+    output "Team" "MP" "W" "D" "L" "P"
+    for (( i=1; i<= nteams; ++i )); do
+        output_team "${order[$i]}"
+    done
+}
+
+load_teams() {
+    # set separator. Note we ignore escaping ';': a\;a;b;win wont work
+    local team1 team2 result
+    local IFS=$';\n'
+
+    while read -r team1 team2 result ; do
+        # should empty result considered as error or ignored? Ignored here.
+        [[ -z "$team1" || -z "$team2" || -z "$result" ]] && continue
+        update_results "$team1" "$team2" "$result"
+    done
+}
+
+# we will accept both argument (file name) or stdin input
+if (( $# == 0 )); then
+    load_teams
+elif [[ -f "$1" ]]; then
+    load_teams < "$1"
+else
+    die Invalid "[$1]" file. Exiting.
+fi
+
+sort_teams
+output_teams
+
+exit 0