HDU 1028 Ignatius and the Princess III(生成函数)

#include<cstdio>
#include<cstring>
#include<algorithm>
const int MAXN = 121;
inline int read() { 
    char c = getchar(); int x = 0, f = 1;
    while(c < ‘0‘ || c > ‘9‘) {if(c == ‘-‘) f = -1; c = getchar();}
    while(c >= ‘0‘ && c <= ‘9‘) x = x * 10 + c - ‘0‘, c = getchar();
    return x * f;
}
int cur[MAXN], nxt[MAXN];
main() {
    int N;
    while(scanf("%d", &N) != EOF) {
        memset(cur, 0, sizeof(cur));
        for(int i = 0; i <= N; i++) cur[i] = 1;
        for(int i = 2; i <= N; i++) {
            for(int j = 0; j <= N; j++) 
                for(int k = 0; j + i * k <= N; k++) 
                    nxt[j + k * i] += cur[j];
            memcpy(cur, nxt, sizeof(nxt));
            memset(nxt, 0, sizeof(nxt));
        }
        printf("%d\n", cur[N]);
    }
    return 0;
}