POJ 2481 Cows

来源：互联网发布：java实现九九乘法表编辑：程序博客网时间：2024/05/16 17:57
解题思路：
实质是排序后求逆序对
#include <iostream>#include <cstring>#include <cstdlib>#include <cstdio>#include <cmath>#include <vector>#include <queue>#include <stack>#include <set>#include <map>#include <algorithm>#define ll long longusing namespace std;const int MAXN = 100000 + 10;struct Node{    int l, r;    int id;    bool operator < (const Node& rhs)const    {        if(l != rhs.l)            return l < rhs.l;        else            return r > rhs.r;    }}cow[MAXN];struct Tree{    int l, r;    int sum;}tree[MAXN<<2];int ans[MAXN];void build(int l, int r, int rt){    tree[rt].l = l;    tree[rt].r = r;    tree[rt].sum = 0;    if(l == r) return ;    int m = (l + r) >> 1;    build(l, m, rt<<1);    build(m + 1, r, rt<<1|1);}void update(int p, int rt){    tree[rt].sum ++;    if(tree[rt].l == tree[rt].r) return ;    else    {        int m = (tree[rt].l + tree[rt].r) >> 1;        if(p <= m) update(p, rt<<1);        else update(p, rt<<1|1);    }}int Query(int l, int r, int rt){    if(tree[rt].l >= l && tree[rt].r <= r)        return tree[rt].sum;    else    {        int m = (tree[rt].l + tree[rt].r) >> 1;        int sum = 0;        if(l <= m) sum += Query(l, r, rt<<1);        if(r > m) sum += Query(l, r, rt<<1|1);        return sum;    }}int main(){    int n;    while(scanf("%d", &n)!=EOF)    {        if(n == 0)            break;        for(int i=0;i<n;i++)        {            scanf("%d%d", &cow[i].l, &cow[i].r);            cow[i].id = i;        }        sort(cow, cow + n);        build(0, MAXN, 1);        for(int i=0;i<n;i++)        {            if(i != 0 && cow[i].l == cow[i-1].l && cow[i].r == cow[i-1].r)                ans[cow[i].id] = ans[cow[i-1].id];            else                ans[cow[i].id] = Query(cow[i].r, MAXN, 1);            update(cow[i].r, 1);        }        for(int i=0;i<n-1;i++)            printf("%d ", ans[i]);        printf("%d\n", ans[n-1]);    }    return 0;}
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