贪心+离散化+线段树上二分。。。 Samara University ACM ICPC 2016-2017 Quarterfinal Qualification Contest G. Of Zorcs and Axes

题目链接:http://codeforces.com/gym/101149/problem/G

题目大意:给你n对数字,为(a[i], b[i]),给你m对数字,为(w[i], c[i])。给n对数字找配对,这个配对必须是m中的,而且m中的每个只能和n中的配对一次。

配对条件,w[i]>=a[j], c[i]>=b[j]即可配对。

输出n个数字,每个数字在m个数字当中的配对。

思路:假定n对数字的是x,m对数字的是y

离散化以后sort一下x和y,这样我们就得到了第一维是排序好了的。

然后我们暴力x,每次都把a[i]的值相同的放入线段树,线段树里面储存的是b[i]。

然后如果a[i] != a[i+1],那么我们就暴力y,对于y,暴力其中所有的w[j] < a[i+1]的,然后再线段树中找离c[i]左边最近的那个数字即可。

ORZ,第一次知道queue这么消耗空间,一直MLE了。

//看看会不会爆int!数组会不会少了一维!
//取物问题一定要小心先手胜利的条件
#include <bits/stdc++.h>
using namespace std;
#pragma comment(linker,"/STACK:102400000,102400000")
#define LL long long
#define ALL(a) a.begin(), a.end()
#define pb push_back
#define mk make_pair
#define fi first
#define se second
#define haha printf("haha
")
const int inf = 0x3f3f3f3f;
const int maxn = 4e5 + 5;
const int maxf = 2e5 + 5;
int n, m;
pair<int, pair<int, int> > a[maxf];
pair<int, pair<int, int> > b[maxf];
vector<int> ve;
vector<int> que[maxn * 2];
/*
线段树上二分,每次找到和当前的pos最靠近的左端的即可。并且每次保存id
*/
struct Tree{
    int cost;
    int lft;
}tree[maxn << 3];
int ans[maxf];

int update(int pos, int l, int r, int o, int add, int ID = 0){
    if (pos == l && pos == r){
        tree[o].cost += add;
        if (add == 1) {que[l].push_back(ID); return 0;}
        if (add == -1) {
            ID = que[l][tree[o].lft]; tree[o].lft++; return ID;
        }
    }
    int mid = (l + r) / 2;
    int id = 0;
    if (pos <= mid) id = update(pos, l, mid, o << 1, add, ID);
    if (pos > mid) id = update(pos, mid + 1, r, o << 1 | 1, add, ID);
    tree[o].cost = tree[o << 1].cost + tree[o << 1 | 1].cost;
    return id;
}

int query(int ql, int qr, int l, int r, int o){
    if (l == r){
        return l;
    }
    int mid = (l + r) / 2;
    int res = 0;
    if (qr > mid && tree[o << 1 | 1].cost > 0)
        res = max(res, query(ql, qr, mid + 1, r, o << 1 | 1));
    if (res == 0 && ql <= mid && tree[o << 1].cost > 0)
        res = max(res, query(ql, qr, l, mid, o << 1));
    return res;
}

void solve(){
    int len = ve.size();
    int pos2 = 1;
    while (b[pos2].fi < a[1].fi) pos2++;
    a[n + 1] = mk(inf, mk(inf, inf));
    for(int i = 1; i <= n; i++){
        update(a[i].se.fi, 1, len, 1, 1, a[i].se.se);
        if(a[i].fi != a[i + 1].fi) {
            while (pos2 <= m && b[pos2].fi < a[i + 1].fi){
                if (tree[1].cost != 0){
                    int x = query(1, b[pos2].se.fi, 1, len, 1);
                    if (x){
                        int id = update(x, 1, len, 1, -1);
                        ans[id] = b[pos2].se.se;
                    }
                }
                pos2++;
            }
        }
    }
    for (int i = 1; i <= n; i++){
        if (ans[i] == 0) {
            printf("-1
"); return;
        }
    }
    for (int i = 1; i <= n; i++){
        printf("%d%c", ans[i], i == n ? '
' : ' ');
    }
}

int main(){
    scanf("%d", &n);
    for (int i = 1; i <= n; i++){
        scanf("%d%d", &a[i].fi, &a[i].se.fi);
        a[i].se.se = i;
        ve.push_back(a[i].fi);
        ve.push_back(a[i].se.fi);
    }
    scanf("%d", &m);
    for (int i = 1; i <= m; i++){
        scanf("%d%d", &b[i].fi, &b[i].se.fi);
        b[i].se.se = i;
        ve.push_back(b[i].fi);
        ve.push_back(b[i].se.fi);
    }
    if (n > m) {
        printf("-1
"); return 0;
    }
    sort(ALL(ve));
    ve.erase(unique(ve.begin(), ve.end()), ve.end());
    for (int i = 1; i <= n; i++){
        a[i].fi = lower_bound(ALL(ve), a[i].fi) - ve.begin() + 1;
        a[i].se.fi = lower_bound(ALL(ve), a[i].se.fi) - ve.begin() + 1;
    }
    for (int i = 1; i <= m; i++){
        b[i].fi = lower_bound(ALL(ve), b[i].fi) - ve.begin() + 1;
        b[i].se.fi = lower_bound(ALL(ve), b[i].se.fi) - ve.begin() + 1;
    }
    sort(a + 1, a + 1 + n);
    sort(b + 1, b + 1 + m);
    solve();
    return 0;
}
View Code
原文地址:https://www.cnblogs.com/heimao5027/p/6816851.html