【HDOJ】2510 符号三角形

暴力打表。

#include <cstdio>
int a[25]={0,0,0,4,6,0,0,12,40,0,0,171,410,0,0,1896,5160,0,0,32757,59984,0,0,431095,822229};
int main() {
    while (scanf("%d",a)!=EOF && *a)
        printf("%d %d
", *a, a[*a]);
    return 0;
}
/*
#include <cstdio>
#include <cstdlib>
#include <cstring>

// '+':1 '-':0
#define MAXN 25
char a[MAXN];
char map[MAXN][MAXN];
int ans;

void f(int i, int n) {
    int j;

    if (i == n) {
        int x, y;

        x = y = 0;
        for (i=0; i<n; ++i) {
            map[0][i] = a[i];
            if (a[i])
                ++x;
            else
                ++y;
        }
        for (i=1; i<n; ++i) {
            for (j=0; j<n-i; ++j) {
                if (map[i-1][j] ^ map[i-1][j+1]) {
                    map[i][j] = 0;
                    ++y;
                } else {
                    map[i][j] = 1;
                    ++x;
                }
            }
        }

        if (x == y)
            ++ans;
    } else {
        for (j=0; j<2; ++j) {
            a[i] = j;
            f(i+1, n);
        }
    }
}

int main() {
    int i;

    for (i=1; i<MAXN; ++i) {
        ans = 0;
        memset(a, 1, sizeof(a));
        f(0, i);
        printf("%d
", ans);
    }

    return 0;
}
*/