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最新推荐文章于 2022-12-23 21:30:38 发布

cozywinter

最新推荐文章于 2022-12-23 21:30:38 发布

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文章标签：算法 c++ 开发语言

本文链接：https://blog.youkuaiyun.com/cozywinter/article/details/127938705

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P1142 轰炸 (计算几何、枚举、排序）

https://www.luogu.com.cn/problem/P1142

/*
 * @Author: xiao-p
 * @Date: 2022-11-13 15:31:35
 * @LastEditors: 304535326@qq.com
 * @LastEditTime: 2022-11-13 16:01:17
 * 304535326@qq.com
 * Copyright (c) 2022 by xiao-p e-mail:304535326@qq.com, All Rights Reserved. 
 */
#include<iostream>
#include<string>
#include<algorithm>
#include<map>
#include<queue>
#include<stack>
#include<set>
#include<math.h>
#include<vector>
#define ll long long
using namespace std;
const int N = 2e4;
int s[N][2];
int main()
{
    int n;
    cin >> n;
    int ans = 1;
    for (int i = 0; i < n; i++)
    {
        cin >> s[i][0] >> s[i][1];
    }
    for (int i = 0; i < n; i++)
    {
        for (int j = i + 1; j < n; j++)
        {
            int tmp = 2;
            for (int x = 0; x < n; x++)
            {
                if (x != i && x != j)
                {
                    if ((s[x][0] - s[j][0]) * (s[j][1] - s[i][1]) == (s[j][0] - s[i][0]) * (s[x][1] - s[j][1]))
                    {
                        tmp++;
                    }
                }
                ans = max(ans, tmp);
            }
        }
    }
    cout << ans ;
}

初次错误因为仅仅判断了横竖

二次错误是判断了横竖和对角线的平行线

应该判断坐标中所有的点，所有的线

斜率的处理转化为交叉相乘后积的判断

P2080 增进感情（搜索 dfs）

/*
 * @Author: xiao-p
 * @Date: 2022-11-13 16:02:26
 * @LastEditors: 304535326@qq.com
 * @LastEditTime: 2022-11-13 16:55:47
 * 304535326@qq.com
 * Copyright (c) 2022 by xiao-p e-mail:304535326@qq.com, All Rights Reserved. 
 */
#include<iostream>
#include<string>
#include<algorithm>
#include<map>
#include<queue>
#include<stack>
#include<set>
#include<math.h>
#include<vector>
#define ll long long
using namespace std;
const int N = 2e4;
#include<iostream>
#include<cstdio>
using namespace std;
int n, v;
int dx[100], dy[100];
int ans = 1e7;
void dfs(int i, int b, int g)
{
    //cout << "asd" << endl;
    if (ans == 0)  return;
    if (i == n)
    {
        if (b+g >= v) ans = min (ans,abs(b - g));
        return ;
    }
    dfs(i+1, b + dx[i], g + dy[i]);
    dfs(i+1, b, g);
}
int main()
{

    cin >> n >> v;
    int tmp = 0;
    for (int i = 0; i < n; i++)
    {
        cin >> dx[i] >> dy[i];
        //tmp += (dx[i] + dy[i]);
    }
    //if (tmp < v) { cout << "-1"; return 0; }
    dfs(0, 0, 0);
    if (ans != 1e7)
    cout << ans;
    else
    cout << "-1";
}

考虑每个点取或不取两种情况的暴搜