From e5a3445606ace2072a4330a3057746e2ad3bb3c2 Mon Sep 17 00:00:00 2001 From: "Steinar H. Gunderson" Date: Tue, 20 Feb 2018 22:50:58 +0100 Subject: [PATCH] Implement correct tiebreak rules for #4 and #6. --- carousel.js | 105 +++++++++++++++++++++++++++++++++++++++++----------- 1 file changed, 83 insertions(+), 22 deletions(-) diff --git a/carousel.js b/carousel.js index 841ae68..4d8e2ec 100644 --- a/carousel.js +++ b/carousel.js @@ -73,7 +73,7 @@ function make_teams_to_idx(teams) return teams_to_idx; } -function partition_by_beat(games, teams) +function partition_by_beat(teams, fill_beatmatrix) { // Head-to-head score by way of components. First construct the beat matrix. let n = teams.length; @@ -85,18 +85,7 @@ function partition_by_beat(games, teams) beat[i][j] = 0; } } - for (let i = 0; i < games.length; ++i) { - let idx1 = teams_to_idx[games[i].name1]; - let idx2 = teams_to_idx[games[i].name2]; - if (idx1 !== undefined && idx2 !== undefined) { - if (games[i].score1 > games[i].score2) { - beat[idx1][idx2] = 1; - } - if (games[i].score1 < games[i].score2) { - beat[idx2][idx1] = 1; - } - } - } + fill_beatmatrix(beat, teams_to_idx); // Floyd-Warshall for transitive closure. for (let k = 0; k < n; ++k) { for (let i = 0; i < n; ++i) { @@ -135,11 +124,11 @@ function partition_by_beat(games, teams) } let result = []; if (better_than_pivot.length > 0) { - result = partition_by_beat(games, better_than_pivot); + result = partition_by_beat(better_than_pivot, fill_beatmatrix); } result.push(equal); // Obviously can't be partitioned further. if (worse_than_pivot.length > 0) { - result = result.concat(partition_by_beat(games, worse_than_pivot)); + result = result.concat(partition_by_beat(worse_than_pivot, fill_beatmatrix)); } return result; } @@ -165,7 +154,20 @@ function rank(games, teams, start_rank, tiebreakers) { } // Rule #1: Head-to-head wins. - let beat_parts = partition_by_beat(games, teams); + let beat_parts = partition_by_beat(teams, function(beat, teams_to_idx) { + for (let i = 0; i < games.length; ++i) { + let idx1 = teams_to_idx[games[i].name1]; + let idx2 = teams_to_idx[games[i].name2]; + if (idx1 !== undefined && idx2 !== undefined) { + if (games[i].score1 > games[i].score2) { + beat[idx1][idx2] = 1; + } + if (games[i].score1 < games[i].score2) { + beat[idx2][idx1] = 1; + } + } + } + }); if (beat_parts.length > 1) { tiebreakers.push(explain_tiebreaker(beat_parts, 'head-to-head')); return subrank_partitions(games, beat_parts, start_rank, tiebreakers); @@ -206,10 +208,45 @@ function rank(games, teams, start_rank, tiebreakers) { return subrank_partitions(games, h2h_gd_parts, start_rank, tiebreakers); } - // Rule #4: Global goal difference. (Well, not strictly, but good enough.) - let gd_parts = partition(teams, function(a, b) { return b.gd - a.gd }); + // Rule #4: Goal difference against common opponents. + var results = {}; + for (let i = 0; i < games.length; ++i) { + if (results[games[i].name1] === undefined) { + results[games[i].name1] = {}; + } + if (results[games[i].name2] === undefined) { + results[games[i].name2] = {}; + } + results[games[i].name1][games[i].name2] = [ games[i].score1, games[i].score2 ]; + results[games[i].name2][games[i].name1] = [ games[i].score2, games[i].score1 ]; + } + let gd_parts = partition_by_beat(teams, function(beat, teams_to_idx) { + for (const team_i of Object.keys(teams_to_idx)) { + let i = teams_to_idx[team_i]; + for (const team_j of Object.keys(teams_to_idx)) { + let j = teams_to_idx[team_j]; + let results_i = results[team_i], results_j = results[team_j]; + let gd_i = 0, gd_j = 0; + + // See if the two teams have both played a third team k. + for (let k in results_i) { + if (!results_i.hasOwnProperty(k)) continue; + if (results_j[k] !== undefined) { + gd_i += results_i[k][0] - results_i[k][1]; + gd_j += results_j[k][0] - results_j[k][1]; + } + } + + if (gd_i > gd_j) { + beat[i][j] = 1; + } else if (gd_i < gd_j) { + beat[j][i] = 1; + } + } + } + }); if (gd_parts.length > 1) { - tiebreakers.push(explain_tiebreaker(gd_parts, 'overall goal difference')); + tiebreakers.push(explain_tiebreaker(gd_parts, 'goal difference versus common opponents')); return subrank_partitions(games, gd_parts, start_rank, tiebreakers); } @@ -220,10 +257,34 @@ function rank(games, teams, start_rank, tiebreakers) { return subrank_partitions(games, h2h_goals_parts, start_rank, tiebreakers); } - // Rule #6: Overall scored goals. (Same caveat as #4.) - let goals_parts = partition(teams, function(a, b) { return b.goals - a.goals }); + // Rule #6: Goals scored against common opponents. + let goals_parts = partition_by_beat(teams, function(beat, teams_to_idx) { + for (const team_i of Object.keys(teams_to_idx)) { + let i = teams_to_idx[team_i]; + for (const team_j of Object.keys(teams_to_idx)) { + let j = teams_to_idx[team_j]; + let results_i = results[team_i], results_j = results[team_j]; + let goals_i = 0, goals_j = 0; + + // See if the two teams have both played a third team k. + for (let k in results_i) { + if (!results_i.hasOwnProperty(k)) continue; + if (results_j[k] !== undefined) { + goals_i += results_i[k][0]; + goals_j += results_j[k][0]; + } + } + + if (goals_i > goals_j) { + beat[i][j] = 1; + } else if (goals_i < goals_j) { + beat[j][i] = 1; + } + } + } + }); if (goals_parts.length > 1) { - tiebreakers.push(explain_tiebreaker(goals_parts, 'scored goals')); + tiebreakers.push(explain_tiebreaker(goals_parts, 'goals scored against common opponents')); return subrank_partitions(games, goals_parts, start_rank, tiebreakers); } -- 2.39.2