P5490 【模板】扫描线

合集 - 洛谷(99)

1.P8755 [蓝桥杯 2021 省 AB2] 负载均衡2023-11-222.P1102 A-B 数对的三种解法2023-11-263.P1090 [NOIP2004 提高组] 合并果子2023-11-264.P3379 【模板】最近公共祖先（LCA）2023-11-285.P8599 [蓝桥杯 2013 省 B] 带分数2023-11-286.P1433 吃奶酪2023-11-297.P3385 【模板】负环2023-12-068.P1576 最小花费2023-12-069.Zuma2023-12-0610.P3205 [HNOI2010] 合唱队2023-12-0611.P1220 关路灯2023-12-0712.P4170 [CQOI2007] 涂色（天赋哥不要点进来）2023-12-1113.P8805 [蓝桥杯 2022 国 B] 机房2023-12-1214.P3386 【模板】二分图最大匹配2023-12-2015.P2197 【模板】Nim 游戏2023-12-2016.P1036 [NOIP2002 普及组] 选数2023-12-2117.T397291 【模板】拓扑排序（加强版）2023-12-2618.P2865 [USACO06NOV] Roadblocks G2023-12-2619.P1168 中位数2024-01-0220.P1631 序列合并2024-01-0221.P3372 【模板】线段树 12024-01-0222.P1352 没有上司的舞会2024-01-0223.P2015 二叉苹果树2024-01-0324.P2014 [CTSC1997] 选课2024-01-0325.P1613 跑路2024-01-0326.P2911 [USACO08OCT] Bovine Bones G2024-01-0427.P4316 绿豆蛙的归宿2024-01-0428.P3870 [TJOI2009] 开关2024-01-1029.P3373 【模板】线段树 22024-01-1430.P1558 色板游戏2024-01-1531.P1638 逛画展2024-01-1632.P1043 [NOIP2003 普及组] 数字游戏2024-01-2633.P1147 连续自然数和2024-01-2634.P1063 [NOIP2006 提高组] 能量项链2024-01-2735.P4342 [IOI1998] Polygon2024-01-2736.P1122 最大子树和2024-02-0537.P2016 战略游戏2024-02-0538.P2585 [ZJOI2006] 三色二叉树2024-02-0739.P1273 有线电视网2024-02-0740.P2986 [USACO10MAR] Great Cow Gathering G2024-02-0741.P1114 “非常男女”计划2024-02-0842.P5026 Lycanthropy2024-02-0843.P4231 三步必杀2024-02-0944.P2985 [USACO10FEB] Chocolate Eating S2024-02-0945.P4090 [USACO17DEC] Greedy Gift Takers P2024-02-1046.P4933 大师2024-02-1047.P1082 [NOIP2012 提高组] 同余方程2024-02-1148.P3811 【模板】模意义下的乘法逆元2024-02-1249.P9725 [EC Final 2022] Chase Game 22024-02-1250.P1330 封锁阳光大学2024-02-1251.P8674 [蓝桥杯 2018 国 B] 调手表2024-02-1252.P10111 [GESP202312 七级] 纸牌游戏2024-02-1453.P9975 [USACO23DEC] Cowntact Tracing 2 B2024-02-1554.P8783 [蓝桥杯 2022 省 B] 统计子矩阵2024-02-1555.P8786 [蓝桥杯 2022 省 B] 李白打酒加强版2024-02-1556.P8807 [蓝桥杯 2022 国 C] 取模2024-02-1557.P8732 [蓝桥杯 2020 国 ABC] 答疑2024-02-1558.P8725 [蓝桥杯 2020 省 AB3] 画中漂流2024-02-1559.P3958 [NOIP2017 提高组] 奶酪2024-02-1560.P4084 [USACO17DEC] Barn Painting G2024-02-1561.P1892 [BOI2003] 团伙2024-02-1662.P1198 [JSOI2008] 最大数2024-02-1663.P1204 [USACO1.2] 挤牛奶Milking Cows2024-02-16

64.P5490 【模板】扫描线2024-02-17

65.P8784 [蓝桥杯 2022 省 B] 积木画2024-02-1766.P9325 [CCC 2023 S2] Symmetric Mountains2024-02-1767.Iva & Pav2024-02-1768.P9889 [ICPC2018 Qingdao R] Plants vs. Zombies2024-02-1769.P9847 [ICPC2021 Nanjing R] Crystalfly2024-02-1870.E. Anna and the Valentine's Day Gift2024-02-1971.F. Chat Screenshots2024-02-1972.G. One-Dimensional Puzzle2024-02-2073.P2899 [USACO08JAN] Cell Phone Network G2024-02-2074.P2023 [AHOI2009] 维护序列2024-02-2075.P1531 I Hate It2024-02-2076.P5057 [CQOI2006] 简单题2024-02-2077.P2357 守墓人2024-02-2078.P8775 [蓝桥杯 2022 省 A] 青蛙过河2024-02-2179.P1656 炸铁路2024-02-2280.Watering an Array2024-02-2381.Dora and Search2024-02-2482.P1137 旅行计划2024-02-2483.P2835 刻录光盘2024-02-2484.P1197 [JSOI2008] 星球大战2024-02-2485.P3388 【模板】割点（割顶）2024-02-2486.P8435 【模板】点双连通分量2024-02-2587.P8436 【模板】边双连通分量2024-02-2588.P2860 [USACO06JAN] Redundant Paths G2024-02-2589.P3067 [USACO12OPEN] Balanced Cow Subsets G2024-02-2690.P4799 [CEOI2015 Day2] 世界冰球锦标赛2024-02-2691.P6492 [COCI2010-2011#6] STEP2024-02-2692.P1653 [USACO04DEC] Cow Ski Area G2024-02-2693.P1040 [NOIP2003 提高组] 加分二叉树2024-03-0394.P5322 [BJOI2019] 排兵布阵2024-03-0395.P2946 [USACO09MAR] Cow Frisbee Team S2024-03-0396.P1156 垃圾陷阱2024-03-0397.P1064 [NOIP2006 提高组] 金明的预算方案2024-03-0498.P3047 [USACO12FEB] Nearby Cows G2024-03-0499.P2466 [SDOI2008] Sue 的小球2024-03-04

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原题链接

题解请移步题解区，相当详细

code

#include<bits/stdc++.h>
using namespace std;

#define ll long long

inline void read(ll &x) {
    x = 0;
    ll flag = 1;
    char c = getchar();
    while(c < '0' || c > '9'){
        if(c == '-')flag = -1;
        c = getchar();
    }
    while(c >= '0' && c <= '9') {
        x = (x << 3) + (x << 1) + (c ^ 48);
        c = getchar();
    }
    x *= flag;
}

inline void write(ll x)
{
    if(x < 0){
        putchar('-');
        x = -x;
    }
    if(x > 9)
        write(x / 10);
    putchar(x % 10 + '0');
}

struct unit
{
    ll y1,y2,x,mark;
}seg[8000005];

struct
{
    ll val;
    ll left;
}tree[8010000];

vector<ll> y(4000005,0);

void pushup(ll node,ll l,ll r)
{
    tree[node].val=tree[node*2].val+tree[node*2+1].val;
}

void change(ll node,ll l,ll r,ll yl,ll yr,ll sit)
{

    if(yl>r||yr<l)return ;
    if(l>=yl&&r<=yr)
    {
        tree[node].left+=sit;
        if(tree[node].left)
        {
            tree[node].val=y[r+1]-y[l];//val代表当前区间生效的长度有多少
        }
        else
        {
            tree[node].val=0;
            pushup(node,l,r);//为什么可以直接不更新子节点后再累加呢？因为子节点当前线段没去过，如果往下更新会错误地改变值。同时子区间已经更新过了
            //说明去掉当前线段后恰好没有了这个区间
        }
        return;
    }

    //有交叉
    ll mid=(l+r)>>1;
    if(mid>=yl)change(node<<1,l,mid,yl,yr,sit);
    if((mid+1)<=yr)change((node<<1)|1,mid+1,r,yl,yr,sit);
    if(!tree[node].left)pushup(node,l,r);
}

bool cmp(unit a,unit b)
{
    return a.x<b.x;
}
int main()
{
    ll n;
    read(n);
    for(ll i=1;i<=n;i++)
    {
        ll x1,x2,y1,y2;
        read(x1); read(y1); read(x2); read(y2);

        if(y1>y2)swap(y1,y2);//y2代表上边界
        if(x1>x2)swap(x1,x2);//x2代表右边界

        y[(i<<1)-1]=y1;//离散化记录
        y[i<<1]=y2;

        seg[(i<<1)-1]={y1,y2,x1,1};
        seg[i<<1]={y1,y2,x2,-1};//记录矩形线段对竖区间的修改
    }

    n<<=1;
    sort(y.begin()+1,y.begin()+n+1);
    ll len=unique(y.begin()+1,y.begin()+1+n)-y.begin()-1;//代表有多少个y点

    sort(seg+1,seg+1+n,cmp);

    ll ans=0;
    for(ll i=1;i<n;i++)
    {
        ll y1=lower_bound(y.begin()+1,y.begin()+len+1,seg[i].y1)-y.begin();
        ll y2=lower_bound(y.begin()+1,y.begin()+len+1,seg[i].y2)-y.begin();//当前线段上下边界的离散值

        change(1,1,len-1,y1,y2-1,seg[i].mark);//减一是因为点与区间的对应关系
        if(seg[i+1].x-seg[i].x>0)  ans+=tree[1].val*(seg[i+1].x-seg[i].x);//就像是公交车，等位于这条竖线上的线段修改全部完成之后才会进入下一步
    }

    write(ans);
    putchar('\n');

    return 0;
}