【BestCoder】 HDOJ 5020 Revenge of Collinearity

STL一下即可。。。

#include <iostream>  #include <queue>  #include <stack>  #include <map>  #include <set>  #include <bitset>  #include <cstdio>  #include <algorithm>  #include <cstring>  #include <climits>#include <cstdlib>#include <cmath>#include <time.h>#define maxn 1005#define maxm 300005#define eps 1e-10#define mod 10000007#define INF 1e9#define lowbit(x) (x&(-x))#define mp make_pair#define ls o<<1#define rs o<<1 | 1#define lson o<<1, L, mid  #define rson o<<1 | 1, mid+1, R  //typedef long long LL;typedef int LL;using namespace std;LL qpow(LL a, LL b){LL res=1,base=a;while(b){if(b%2)res=res*base;base=base*base;b/=2;}return res;}LL powmod(LL a, LL b){LL res=1,base=a;while(b){if(b%2)res=res*base%mod;base=base*base%mod;b/=2;}return res;}void scanf(int &__x){__x=0;char __ch=getchar();while(__ch==' '||__ch=='\n')__ch=getchar();while(__ch>='0'&&__ch<='9')__x=__x*10+__ch-'0',__ch = getchar();}LL gcd(LL _a, LL _b){if(!_b) return _a;else return gcd(_b, _a%_b);}// headstruct node{int x, y;}p[maxn];map<pair<int, int>, int> mpp;pair<int, int> v;int n;void read(void){scanf("%d", &n);for(int i = 1; i <= n; i++) scanf("%d%d", &p[i].x, &p[i].y);}void work(void){int x, y, t;long long ans = 0, tt;for(int i = 1; i <= n; i++) {mpp.clear();for(int j = i + 1; j <= n; j++) {x = p[j].x - p[i].x;y = p[j].y - p[i].y;t = gcd(x, y);x /= t, y /= t;v = mp(x, y);if(!mpp.count(v)) mpp[v] = 1;else {mpp[v]++;tt = mpp[v] - 1;ans -= tt * (tt - 1) / 2;tt++;ans += tt * (tt - 1) / 2;}}}printf("%I64d\n", ans);}int main(void){int _;while(scanf("%d", &_)!=EOF) {while(_--) {read();work();}}return 0;}