HDU 4597 Play Game

题目链接

有两个双端队列每次每人可以从任意一堆的头或尾取值,两人均采取最优策略,问先手的最后得分

很简单的博弈

#include <cstdio>
#include <cstring>
#include <iostream>
using namespace std;
const int inf = 1000000000;
int T, N, A[25], B[25], f[25][25][25][25];
int DP(int a, int b, int c, int d) {
	int turn = N - (b - a + 1) + N - (d - c + 1);
	if(turn == (N << 1)) return 0;
	int & res = f[a][b][c][d];
	if(res != -1) return res;
	if(turn & 1) {
		res = inf;
		if(a <= b) res = min(res, DP(a + 1, b, c, d));
		if(a <= b) res = min(res, DP(a, b - 1, c, d));
		if(c <= d) res = min(res, DP(a, b, c + 1, d));
		if(c <= d) res = min(res, DP(a, b, c, d - 1));
	}
	else {
		res = 0;
		if(a <= b) res = max(res, DP(a + 1, b, c, d) + A[a]);
		if(a <= b) res = max(res, DP(a, b - 1, c, d) + A[b]);
		if(c <= d) res = max(res, DP(a, b, c + 1, d) + B[c]);
		if(c <= d) res = max(res, DP(a, b, c, d - 1) + B[d]);
	}
	return res;
}
int main() {
	scanf("%d", &T);
	for(int kase = 1; kase <= T; kase++) {
		scanf("%d", &N);
		for(int i = 1; i <= N; i++) {
			scanf("%d", &A[i]);
		}
		for(int i = 1; i <= N; i++) {
			scanf("%d", &B[i]);
		}
		memset(f, -1, sizeof(f));
		printf("%d\n", DP(1, N, 1, N));
	}
	return 0;
}