二分查找算法实现-优快云博客

本文介绍了一种基于二分查找算法的应用实例，通过具体的代码实现展示了如何在一个有序数组中查找指定元素的位置，并针对特定场景进行了优化。

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简单题，二分查找

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#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <algorithm>
using namespace std;

#define maxn 5005

struct Line
{
int u, d;
} line[maxn];

int n, m, x1, x2, y1, y2;
int toy[maxn];

bool left(int x, int y, Line a)
{
if (x < a.d + (y - y2) * (a.u - a.d) * 1.0 / (y1 - y2))
return true;
return false;
}

int binarysearch(int x, int y)
{
int l = 0, r = n;
int mid;

while (l < r)
{
mid = (l + r) / 2;
if (left(x, y, line[mid]))
r = mid;
else
l = mid + 1;
}
return l;
}

int main()
{
//freopen("t.txt", "r", stdin);
while (scanf("%d", &n), n != 0)
{
memset(toy, 0, sizeof(toy));
scanf("%d%d%d%d%d", &m, &x1, &y1, &x2, &y2);
for (int i = 0; i < n; i++)
scanf("%d%d", &line[i].u, &line[i].d);
for (int i = 0; i < m; i++)
{
int x, y;
scanf("%d%d", &x, &y);
toy[binarysearch(x, y)]++;
}
for (int i = 0; i <= n; i++)
printf("%d: %d\n", i, toy[i]);
printf("\n");
}
return 0;
}

转载于:https://www.cnblogs.com/rainydays/archive/2011/05/23/2054818.html