COJ 1163 寒衣调（校赛D题）

http://acm.csu.edu.cn/OnlineJudge/problem.php?id=1163

a[i - 1]表示i的前缀积，b[i + 1]表示i的后缀积，两者相乘取模就是所需的结果

#include<cstdio>
#define MAXN 100005
int a[MAXN], b[MAXN];
int n, m;
int main()
{
    while(scanf( "%d%d", &n, &m) == 2){
        for(int i = 0; i < n; i ++)
            scanf("%d",&a[i]);
        b[n] = 1;
        for(int i = n - 1; i >= 0; i --)
            b[i] = (long long)b[i + 1] * a[i] % m;
        for(int i = 1; i < n; i ++)
            a[i] = (long long)a[i - 1] * a[i] % m;
        printf( "%lld", (long long)b[1]);
        for(int i = 1; i < n; i ++)
            printf(" %lld", (long long)a[i - 1] * b[ i + 1] % m);
        printf("\n");
    }
    return 0;
}