学步园

　　昨晚想着做了的，到宿舍乱的又没心情了。发现高精度真的不熟，各种错误，Crash， MLE， WA。。。最后看到有人一个数组空间存两位数，精度为100时才不MLE。

#include <iostream>
#include <cstdio>
#include <cstring>

using namespace std;

const int N = 1000;

int ans[N*2][N+1];
int tmp[N+1];

void add(int a[], int b[], int res[]){
int i;
for(i = N; i >= 0; i--){
        res[i] = a[i] + b[i];
    }
for(i = N; i >= 0; i--){
        res[i-1] += res[i]/100;
        res[i] %= 100;
    }
}

void mul(int  a[], int k, int res[]){
int i;
for(i = N; i >= 0; i--){
        res[i] = a[i] * k;
    }
for(i = N; i >= 0; i--){
        res[i-1] += res[i]/100;
        res[i] %= 100;
    }
}

void print(int res[]){
int i = 0;
while(res[i] == 0)     i++;
    printf("%d", res[i++]);
for(; i <= N; i++){
if(res[i] > 9)
            printf("%d", res[i]);
else
            printf("0%d", res[i]);
    }
    putchar('\n');
}

int main(){
//freopen("data.in", "r", stdin);

int n, k, i;
while(scanf("%d%d", &n, &k) != EOF){
//printf("%d %d\n", n, k);
        memset(ans, 0, sizeof(ans));

        ans[0][N] = k-1;
        ans[1][N] = k*(k-1);

for(i = 2; i < n; i++){
            memset(tmp, 0, sizeof(tmp));
            add(ans[i-1], ans[i-2], tmp);
            mul(tmp, k-1, ans[i]);
        }
        print(ans[n-1]);
    }
return 0;
}