Moved solver in a struct

1 files changed, 0 insertions, 67 deletions

diff --git a/src/solve.rs b/src/solve.rs
deleted file mode 100644
index 9561ff1..0000000
--- a/src/solve.rs
+++ /dev/null
@@ -1,67 +0,0 @@
-use std::collections::HashMap;
-
-use crate::position::{Position, WIDTH, HEIGHT, MIN_SCORE};
-
-const COLUMNS_ORDER: [u64; 7] = [3, 2, 4, 1, 5, 0, 6];
-
-pub fn solve(p: Position) -> i32 {
-    let mut cache = HashMap::with_capacity(30000);
-    solve_rec(p, -1000, 1000, &mut cache)
-}
-
-// the weak solver only tells if the position is a win/lose/draw
-// it's faster but less precise
-pub fn solve_weak(p: Position) -> i32 {
-    let mut cache = HashMap::with_capacity(30000);
-    solve_rec(p, -1, 1, &mut cache)
-}
-
-fn solve_rec(p: Position, a: i32, b: i32, cache: &mut HashMap<u64, i32>) -> i32 {
-    if p.is_draw() {
-        return 0;
-    }
-    for x in 0..WIDTH {
-        if p.is_valid_play(x) && p.is_winning_play(x) {
-            return (((WIDTH * HEIGHT + 1) as i32) - (p.play_count as i32)) / 2;
-        }
-    }
-
-    let mut alpha = a;
-    let mut beta = b;
-
-    if let Some(max_score) = cache.get(&p.key()) {
-        // can't return max_score directly
-        // because the alpha-beta context in the cache may be
-        // different than the current alpha-beta
-        if beta > *max_score {
-            beta = *max_score;
-            if alpha >= beta {
-                return beta;
-            }
-        }
-    }
-
-    let mut best = MIN_SCORE;
-    for x in (0..(WIDTH as usize))
-                .map(|x| COLUMNS_ORDER[x])
-                .filter(|x| p.is_valid_play(*x))
-    {
-        // using negamax, variante of minimax where:
-        // max(player1, player2) == -min(-player1, -player2)
-        let score = -solve_rec(p.play(x), -beta, -alpha, cache);
-        if score > best {
-            best = score;
-        }
-        // reduce alpha-beta range if found better score
-        if best > alpha {
-            alpha = best;
-        }
-        // impossible alpha-beta range reached (alpha is supposed to be < to beta)
-        if alpha >= beta {
-            return score;
-        }
-    }
-    cache.insert(p.key(), best);
-    return best;
-}
-