HDU 1176 免費餡餅(DP)

很顯然的DP。。dp[i][j], i秒位置在j的最大接餅數

代碼：

#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;

const int N = 100005;
const int INF = 0x3f3f3f3f;

int n;
int dp[N][11], g[N][11];

int main() {
    while (~scanf("%d", &n) && n) {
        int Max = 0;
        int x, y;
        memset(g, 0, sizeof(g));
        while (n--) {
            scanf("%d%d", &x, &y);
            g[y][x]++;
            Max = max(Max, y);
        }
        int ans = 0;
        for (int i = 0; i <= 10; i++) {
            if (i != 5) dp[0][i] = -INF;
        }
        for (int i = 1; i <= Max; i++) {
            dp[i][0] = max(dp[i - 1][0], dp[i - 1][1]) + g[i][0];
            for (int j = 1; j < 10; j++)
                dp[i][j] = max(max(dp[i - 1][j - 1], dp[i - 1][j]), dp[i - 1][j + 1]) + g[i][j];
            dp[i][10] = max(dp[i - 1][9], dp[i - 1][10]) + g[i][10];
        }
        for (int i = 0; i <= 10; i++) ans = max(ans, dp[Max][i]);
        printf("%d\n", ans);
    }
    return 0;
}