Ural 1019 A Line Painting (line segment tree, segment update discretization)

Link:

Http://acm.timus.ru/problem.aspx? Space = 1 & num = 1019

Question:

A line segment is a bit 0 ~ 10 ^ 9. All are white at the beginning. Then there will be some operations: to dye the [a B] area into white, or to dye the [a, B] area into black.

Finally, find the longest white section.

Analysis and Summary:

Segment update Dyeing of line segments. Of course, because the data volume is small, it can also be directly violent.

1. I have been stuck on the discretization issue for a long time and Wa many times, mainly because the point of the line segment is 0 ~ 10 ^ 9,0 and 10 ^ 9 must be added.

2. When scanning consecutive white intervals, pay attention to the end boundary.

Code:

1. Line Segment tree

#include<iostream>#include<cstdio>#include<cstring>#include<algorithm>using namespace std;#define STOP puts("Stop here~");#define FF(i,n) for(int i=0; i<(n); ++i)#define FOR(i,s,t) for(int i=(s); i<(t); ++i)#define mid ((left+right)>>1)#define lson rt<<1, left, m#define rson rt<<1|1, m+1, rightconst int MAXN = 100000;int col[MAXN],arr[MAXN<<1];int A[MAXN],B[MAXN];char C[MAXN];int vis[MAXN];void update(int rt,int left,int right,int l,int r,int data){    if(l<=left && right<=r){        col[rt] = data;        return;    }    if(col[rt] == data) return;    if(col[rt] != -1){        col[rt<<1] = col[rt<<1|1] = col[rt];        col[rt] = -1;    }    int m = mid;    if(l <= m) update(lson,l,r,data);    if(r > m) update(rson,l,r,data);}void query(int rt,int left,int right){    if(col[rt] >= 0){        FOR(i,left,right+1) vis[i]=col[rt];        return;    }    if(left!=right && col[rt]==-1){        int m = mid;        query(lson);        query(rson);    }}int binary(int left,int right,int x){    while(left < right){        int m = (left+right)>>1;        if(arr[m] >= x) right=m;        else left=m+1;    }    return left;}int main(){    int n; char ch[3];    while(~scanf("%d",&n)){        int kk=0;        arr[kk++] = 0;        arr[kk++] = 1e9;        FF(i,n){            scanf("%d%d%s",&A[i],&B[i],ch);            C[i] = ch[0];            arr[kk++]=A[i]; arr[kk++]=B[i];        }        sort(arr,arr+kk);        int end = kk;        kk = 1;        FOR(i,1,end){            if(arr[i]!=arr[i-1])arr[kk++]=arr[i];        }        end = kk;        FOR(i,1,end){            if(arr[i]>arr[i-1]+1) arr[kk++]=arr[i-1]+1;        }        sort(arr,arr+kk);        memset(col,-1,sizeof(col));        col[1] = 0;        FF(i,n){            int a=binary(0,kk,A[i]);            int b=binary(0,kk,B[i]);            if(C[i]=='b'){                update(1,1,kk-1,a+1,b,1);            }            else{                update(1,1,kk-1,a+1,b,0);            }        }        int i=1,maxx=-1,ans_x=0,ans_y=kk-1;        query(1,1,kk-1);        memcpy(col,vis,sizeof(vis));        while(i<kk){            if(col[i]==0){                int j = i+1;                while(col[j]==0 && j<kk)++j;                --j;                int ll=arr[j]-arr[i-1];                if(ll > maxx){                    maxx=ll;                    ans_x=i-1; ans_y=j;                }                i = j;            }            ++i;        }        printf("%d %d\n",arr[ans_x], arr[ans_y]);    }    return 0;}

2. Violence

#include<iostream>#include<cstdio>#include<cstring>#include<algorithm>using namespace std;#define STOP puts("Stop here~");#define FF(i,n) for(int i=0; i<(n); ++i)#define FOR(i,s,t) for(int i=(s); i<(t); ++i)const int MAXN = 100000;int col[MAXN],arr[MAXN<<1];int A[MAXN],B[MAXN];char C[MAXN];int binary(int left,int right,int x){    while(left < right){        int m = (left+right)>>1;        if(arr[m] >= x) right=m;        else left=m+1;    }    return left;}int main(){    int n; char ch[3];    while(~scanf("%d",&n)){        int kk=0;        arr[kk++] = 0;        arr[kk++] = 1e9;        FF(i,n){            scanf("%d%d%s",&A[i],&B[i],ch);            C[i] = ch[0];            arr[kk++]=A[i]; arr[kk++]=B[i];        }        sort(arr,arr+kk);        int end = kk;        kk = 1;        FOR(i,1,end){            if(arr[i]!=arr[i-1])arr[kk++]=arr[i];        }        end = kk;        FOR(i,1,end){            if(arr[i]>arr[i-1]+1) arr[kk++]=arr[i-1]+1;        }        sort(arr,arr+kk);        memset(col,0,sizeof(col));        FF(i,n){            int a=binary(0,kk,A[i]);            int b=binary(0,kk,B[i]);            if(C[i]=='b'){                FOR(i,a+1,b+1)col[i]=1;            }            else{                FOR(i,a+1,b+1)col[i]=0;            }        }        int i=1,maxx=-1,ans_x=0,ans_y=kk-1;        while(i<kk){            if(col[i]==0){                int j = i+1;                while(col[j]==0 && j<kk)++j;                --j;                int ll=arr[j]-arr[i-1];                if(ll > maxx){                    maxx=ll;                    ans_x=i-1; ans_y=j;                }                i = j;            }            ++i;        }        printf("%d %d\n",arr[ans_x], arr[ans_y]);    }    return 0;}

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Original Http://blog.csdn.net/shuangde800,
D_double (reprinted please mark)