Codeforces731E Funny Game

Posted 2020-08-15

dp[i][0]表示从i出发，轮到先手走的最优值。

dp[i][1]表示从i出发，轮到后手走的最优值。

dp[i][0]=max(dp[j][1]+sum[j])

dp[i][1]=min(dp[j][0]-sum[j])

倒着推就好了。

 1 #include <bits/stdc++.h>
 2 using namespace std;
 3 
 4 int a[200010];
 5 int dp[200010][2];
 6 int sum[200010];
 7 
 8 int main()
 9 {
10     int n;
11     scanf("%d", &n);
12     for (int i = 1; i <= n; i++)
13         scanf("%d", a + i), sum[i] = sum[i - 1] + a[i];
14     int houShouMax = sum[n], xianShouMin = -sum[n];
15     for (int i = n - 1; i >= 1; i--)
16     {
17         dp[i][0] = houShouMax;
18         dp[i][1] = xianShouMin;
19         houShouMax = max(houShouMax, dp[i][1] + sum[i]);
20         xianShouMin = min(xianShouMin, dp[i][0] - sum[i]);
21     }
22     printf("%d", dp[1][0]);
23     return 0;
24 }