题意:给定n匹马,要求出可能的排名情况(可能并列)
思路:递推,dp[i][j]表示i匹马的时候有j种不同名次,那么dp[i][j]可以由dp[i - 1][j - 1]插入j个不同位置得来,或者由dp[i - 1][j]放入已有j的名次得来,得到递推式dp[i][j] = j * (dp[i - 1][j - 1] + dp[i - 1][j]); 然后对于n的答案为sum{dp[n][j]} (1 <= j <= n)
代码:
#include <stdio.h>
#include <string.h>
const int MOD = 10056;
const int N = 1005;
int t, n, dp[N][N], ans[N];
void init() {
dp[0][0] = 1;
for (int i = 1; i <= 1000; i++) {
int sum = 0;
for (int j = 1; j <= i; j++) {
dp[i][j] = (dp[i - 1][j - 1] + dp[i - 1][j]) % MOD * j % MOD;
sum = (sum + dp[i][j]) % MOD;
}
ans[i] = sum;
}
}
int main() {
int cas = 0;
init();
scanf("%d", &t);
while (t--) {
scanf("%d", &n);
printf("Case %d: %d\n", ++cas, ans[n]);
}
return 0;
}
UVA 12034 - Race(递推),布布扣,bubuko.com
原文:http://blog.csdn.net/accelerator_/article/details/26740205