uva-11134
題意:指定n個矩形,并在每個矩形里面放一個戰車,要求戰車不能相互攻擊。
分析:貪心算法,將二維坐標分解成兩個一維x,y。分別找出x,y不會重合的部分。
#include<iostream> #include<string.h> #include<sstream> #include<algorithm> #include<vector> using namespace std; int n; struct MyStruct {int l,r,id;bool operator<(const MyStruct &u) {if (r == u.r)return l < u.l;return r < u.r;} }x[10000+100],y[10000 + 100]; int main() {int xz[10000 + 100]; int yz[10000 + 100];int vis[10000 + 100];while (cin >> n&&n) {memset(vis, 0, sizeof(vis));for (int i = 0; i < n; i++) {cin >> x[i].l >> y[i].l >> x[i].r >> y[i].r;x[i].id = i; y[i].id = i;}sort(x, x + n);sort(y, y + n);int ok = 0;for (int i = 0; i < n; i++) {ok = 0;for (int j = x[i].l; j <= x[i].r; j++) {if (!vis[j]) {xz[x[i].id] = j;vis[j] = 1;ok = 1;break;}}if (!ok) {cout << "IMPOSSSIBLE" << endl;break;}}if (!ok)continue;ok = 0;memset(vis, 0, sizeof(vis));for (int i = 0; i < n; i++) {ok = 0;for (int j = y[i].l; j <= y[i].r; j++) {if (!vis[j]) {yz[y[i].id] = j;vis[j] = 1;ok = 1;break;}}if (!ok) {cout << "IMPOSSSIBLE" << endl;break;}}if (!ok)continue;for (int i = 0; i < n; i++) {cout << xz[i] <<" "<< yz[i] << endl;}}return 0; }?
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