例题8-4 传说中的车（Fabled Rooks, UVa 11134）

由于行列之间是没有任何联系的，可以把行列分开来讨论。。orz。。
memset使用错误。。在函数中sizeof指针无法清零。
考虑区间与点的对应时，可以由区间来选点，也可以由点来选区间，
对于每个点，选择以该点为起点，长度最小的区间。

#include <set>#include <map>#include <ctime>#include <cmath>#include <stack>#include <queue>#include <deque>#include <cstdio>#include <string>#include <vector>#include <cctype>#include <sstream>#include <utility>#include <cstring>#include <cstdlib>#include <iostream>#include <algorithm>#define SF(a) scanf("%d", &a)#define PF(a) printf("%d\n", a)  #define SFF(a, b) scanf("%d%d", &a, &b)  #define SFFF(a, b, c) scanf("%d%d%d", &a, &b, &c)#define SFFFF(a, b, c, d) scanf("%d%d%d%d", &a, &b, &c, &d)#define CLEAR(a, b) memset(a, b, sizeof(a))#define IN() freopen("in.txt", "r", stdin)#define OUT() freopen("out.txt", "w", stdout)#define FOR(i, a, b) for(int i = a; i < b; ++i)#define LL long long#define maxn 5005#define maxm 205#define mod 1000000007#define INF 10000007#define eps 1e-4using namespace std;//-------------------------CHC------------------------------//int n;int xl[maxn], xr[maxn], yl[maxn], yr[maxn];int px[maxn], py[maxn];bool inside(int x, int l, int r) { return l <= x && x <= r; }bool solve(int *l, int *r, int *p) {memset(p, 0, sizeof(int)*n);FOR(i, 1, n + 1) {int cur = -1, mind = INF;FOR(j, 0, n) if (!p[j] && inside(i, l[j], r[j]) && mind > r[j])mind = r[j], cur = j;if (cur < 0) return false;p[cur] = i;}return true;}int main() {while (SF(n) && n) {FOR(i, 0, n) SFFFF(xl[i], yl[i], xr[i], yr[i]);if (!solve(xl, xr, px) || !solve(yl, yr, py)) puts("IMPOSSIBLE");else FOR(i, 0, n) printf("%d %d\n", px[i], py[i]);}return 0;}