HDU 4701

题目大意是：有N个物品，每个物品有Ci个价值，ALICE和BOB分别有A, B元钱，依次购买（即买第i个物品前i-1物品必须买完），直到有一人无法购买。问ALICE是否有必胜策略。

博弈论和DP结合，具体见代码：

 1 /*
 2 ID:esxgx1
 3 LANG:C++
 4 PROG:hdu4701
 5 */
 6 #include <cstdio>
 7 #include <cstring>
 8 #include <iostream>
 9 #include <algorithm>
10 using namespace std;
11 
12 int _s[1000007], *s = &_s[1];
13 int dp[1000007];
14 
15 int main(void)
16 {
17     #ifndef ONLINE_JUDGE
18     freopen("in.txt", "r", stdin);
19     #endif
20 
21     int N, A, S;
22     while(scanf("%d%d%d", &N, &A, &S) > 0) {
23         S += A;
24         s[-1] = 0;
25         for(int i=0; i<N; ++i) {
26             int a;
27             scanf("%d", &a);
28             s[i] = s[i-1] + a;
29         }
30         /* O(n2)
31         for(int i=N; i--; ) {
32             dp[i] = s[N-1] - s[i-1];
33             for(int j = i+1; j<N; ++j)
34                 dp[i] = min(dp[i], max(s[j-1] - s[i-1], S - s[i-1] - dp[j] + 1));
35         }*/
36         int minn = s[N-1];
37         for(int i=N; i--; ) {
38             dp[i] = min(s[N-1], minn) - s[i-1];
39             minn = min(minn, max(s[i-1], S - dp[i] + 1));
40         }
41         printf(A >= dp[0] ? "ALICE
": "BOB
");
42     }
43     return 0;
44 }

2014-10-01 15:20:55

Accepted

4701

453MS

8124K

662 B

G++