[uva] 10167 - Birthday Cake

http://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&category=107&page=show_problem&problem=1108

开始和大家一起刷白书的课后题了! 第一道, 枚举题.

#include <cstdio>
#include <utility>
#include <vector>
using namespace std;

bool solve(vector<pair<int, int> > & v, int n, int i, int j) {
    
    int lnum = 0, unum = 0;
    for (int k = 0; k < 2 * n; ++k) {
        int s = i * v[k].first + j * v[k].second;
        if (s > 0) {
            lnum += 1;
        } else if (s < 0) {
            unum += 1;
        } else {
            return false;
        }
    }
    if (lnum == unum && lnum == n) {
        //printf("%d\n", lnum);
        printf("%d %d\n", i, j);
        return true;
    }
    return false;
}

int main()
{
    int n = 0;
    while(true) {
        scanf("%d", &n);
        if (n == 0)break;
        vector<pair<int, int> > v(2 * n);
        for (int i = 0; i < 2 * n; ++i) {
            pair<int, int> p;
            scanf("%d%d", &p.first, &p.second);
            v[i] = p;
            //printf("%d, %d\n",  v[i].first, v[i].second);
        }
        for (int i = -500; i <= 500; ++i) {
            int flag = 0;
            for (int j = -500; j <= 500; ++j) {
                if (solve(v, n, i, j)) {
                    flag = 1;
                    break;
                }
            }
            if (flag) break;
        }
    }
    return 0;
}