hdu 2461(AC) & poj 3695(TLE)(离散化+矩形并)

Rectangles

Time Limit: 5000/4000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 1503    Accepted Submission(s): 777


Problem Description
You are developing a software for painting rectangles on the screen. The software supports drawing several rectangles and filling some of them with a color different from the color of the background. You are to implement an important function. The function answer such queries as what is the colored area if a subset of rectangles on the screen are filled.
 
Input
The input consists of multiple test cases. Each test case starts with a line containing two integers N(1 ≤ N ≤ 20) and M(1 ≤ M ≤ 100000), indicating the number of rectangles on the screen and the number of queries, respectively.
The i-th line of the following N lines contains four integers X1,Y1,X2,Y2 (0 ≤ X1 < X2 ≤ 1000, 0 ≤ Y1 < Y2 ≤ 1000), which indicate that the lower-left and upper-right coordinates of the i-th rectangle are (X1, Y1) and (X2, Y2). Rectangles are numbered from 1 to N.
The last M lines of each test case describe M queries. Each query starts with a integer R(1<=R ≤ N), which is the number of rectangles the query is supposed to fill. The following list of R integers in the same line gives the rectangles the query is supposed to fill, each integer of which will be between 1 and N, inclusive.

The last test case is followed by a line containing two zeros.
 
Output
For each test case, print a line containing the test case number( beginning with 1).
For each query in the input, print a line containing the query number (beginning with 1) followed by the corresponding answer for the query. Print a blank line after the output for each test case.
 
Sample Input
2 2 0 0 2 2 1 1 3 3 1 1 2 1 2 2 1 0 1 1 2 2 1 3 2 2 1 2 0 0
 
Sample Output
Case 1: Query 1: 4 Query 2: 7 Case 2: Query 1: 2
 
Source
 题意:给你n个矩形,然后m个询问,每次询问 1-n个矩形的并面积.
题解:我的方法就是每次询问的时候然后再一个个的去查询。。优化了好久,poj还是TLE hdu 1185MS水过
///离散化
#include <iostream>
#include <stdio.h>
#include <algorithm>
#include <string.h>
#include <cmath>
using namespace std;
const int N = 21;
struct Rec
{
    int x1,y1,x2,y2;
} rec[N];
int x[N*2],y[N*2];
int vis[N*2][N*2];
int k,n,t,m;
int binary1(int l,int r,int value)
{
    int mid;
    while(l<r)
    {
        mid = (l+r)>>1;
        if(x[mid]==value) return mid;
        if(x[mid]<value) l = mid+1;
        else r = mid-1;
    }
    return l;
}
int binary2(int l,int r,int value)
{
    int mid;
    while(l<r)
    {
        mid = (l+r)>>1;
        if(y[mid]==value) return mid;
        if(y[mid]<value) l = mid+1;
        else r = mid-1;
    }
    return l;
}
int k1,k2;
void input()
{
    k=0,t=0;
    int x1,y1,x2,y2;
    for(int i=0; i<n; i++)
    {
        scanf("%d%d%d%d",&x1,&y1,&x2,&y2);
        rec[t].x1 = x1,rec[t].y1 = y1,rec[t].x2=x2,rec[t++].y2 = y2;
        x[k] = x1,y[k++] = y1;
        x[k] = x2,y[k++] = y2;
    }
    sort(x,x+k);
    sort(y,y+k);
    k1 = 0,k2=0;
    x[k1] = x[0];
    y[k2] = y[0];
    for(int i=1;i<k;i++){ ///去重还是TLE
        if(x[i]!=x[i-1]) x[++k1] = x[i];
        if(y[i]!=y[i-1]) y[++k2] = y[i];
    }
}
int solve(int num)
{
    memset(vis,0,sizeof(vis));
    while(num--)
    {
        int b;
        scanf("%d",&b);
        int t1,t2,t3,t4;
        t1 = binary1(0,k1,rec[b-1].x1);
        t2 = binary1(0,k1,rec[b-1].x2);
        t3 = binary2(0,k2,rec[b-1].y1);
        t4 = binary2(0,k2,rec[b-1].y2);
        for(int j=t1; j<t2; j++)
        {
            for(int l = t3; l<t4; l++)
            {
                vis[j][l] = 1;
            }
        }
    }
    int area = 0;
    for(int i=0; i<=k1; i++)
    {
        for(int j=0; j<=k2; j++)
        {
            area+=vis[i][j]*(x[i+1]-x[i])*(y[j+1]-y[j]);
        }
    }
    return area;
}
int main()
{
    int x1,y1,x2,y2;
    int cnt = 1;
    while(scanf("%d%d",&n,&m)!=EOF&&n+m)
    {

        input();
        int a,b;
        printf("Case %d:
",cnt++);
        int cas = 1;
        while(m--)
        {
            scanf("%d",&a);
            printf("Query %d: %d
",cas++,solve(a));;
        }
        printf("
");
    }
    return 0;
}
原文地址:https://www.cnblogs.com/liyinggang/p/5463161.html