From: Stephen Seo <seo.disparate@gmail.com>
Date: Mon, 7 Mar 2022 07:59:18 +0000 (+0900)
Subject: Tweak Hard-level AI
X-Git-Tag: sprint_02_day_1~2
X-Git-Url: https://git.seodisparate.com/stephenseo/static/git-favicon.png?a=commitdiff_plain;h=ec9aac84004088919388f16ee95168c70a985dca;p=EN605.607.81.SP22_ASDM_Project

Tweak Hard-level AI

Shuffles the utilities-index pairs for the cases where there are
multiple pairs of the same utility value.
---

diff --git a/front_end/src/ai.rs b/front_end/src/ai.rs
index 87226c2..967d033 100644
--- a/front_end/src/ai.rs
+++ b/front_end/src/ai.rs
@@ -115,12 +115,19 @@ pub fn get_ai_choice(
         AIDifficulty::Easy => pick_some_of_choices(AI_EASY_MAX_CHOICES),
         AIDifficulty::Normal => pick_some_of_choices(AI_NORMAL_MAX_CHOICES),
         AIDifficulty::Hard => {
+            let mut utilities: Vec<(usize, f64)> = utilities.into_iter().enumerate().collect();
+            // shuffle utilities for the cases where there are equivalent utilities
+            if utilities.len() > 1 {
+                for i in 1..utilities.len() {
+                    utilities.swap(i, thread_rng().gen_range(0..=i));
+                }
+            }
             // only pick the best option all the time
-            let mut max = 0.0f64;
+            let mut max = -1.0f64;
             let mut max_idx: usize = 0;
-            for (idx, utility) in utilities.iter().enumerate() {
-                if *utility > max {
-                    max = *utility;
+            for (idx, utility) in utilities {
+                if utility > max {
+                    max = utility;
                     max_idx = idx;
                 }
             }