POJ 1064 分割线缆（二分查找）

/**
 * @description: poj1064，多根电缆切成指定段数（相同长度），求每段最大长度
 * @author: michael ming
 * @date: 2019/5/2 15:14
 * @modified by: 
 */
#include <iostream>
#include <iomanip>
#include <stdio.h>
#include <cmath>
using namespace std;
int main()
{
    int cables, target, cable_we_get;
    cin >> cables >> target;
    double minlen = 0.0, maxlen = 100000, mid, len[10001];
    for(int i = 0; i < cables; ++i)
    {
//        cin >> len[i];
        scanf("%lf", &len[i]);
//        len[i] += 1E-15;
//        maxlen = maxlen > len[i] ? maxlen : len[i];
    }
    while(maxlen - minlen > 1E-3)
    {
        cable_we_get = 0;
        mid = minlen + (maxlen - minlen)/2;
        for(int i = 0; i < cables; ++i)
        {
            cable_we_get += (int)(len[i]/mid);
        }
        if(cable_we_get >= target)
            minlen = mid;
        else
            maxlen = mid;
    }
//    mid = double(floor(mid*100))/100.0;
//    cout << fixed << setprecision(2) << mid << endl;
    printf("%.2lf\n", floor(mid*100)/100);
    return 0;
}

/**
 * @description: poj1064，多根电缆切成指定段数（相同长度），求每段最大长度
 * @author: michael ming
 * @date: 2019/5/2 15:14
 * @modified by: 
 */
#include <iostream>
#include <iomanip>
#include <stdio.h>
#include <cmath>
using namespace std;
int main()
{
    int cables, target, cable_we_get;
    cin >> cables >> target;
    double minlen = 0.0, maxlen = 100000, mid, len[10001];
    for(int i = 0; i < cables; ++i)
    {
        cin >> len[i];
//        scanf("%lf", &len[i]);
    }
    while(maxlen - minlen > 1E-3)
    {
        cable_we_get = 0;
        mid = minlen + (maxlen - minlen)/2;
        for(int i = 0; i < cables; ++i)
        {
            cable_we_get += (int)(len[i]/mid);
        }
        if(cable_we_get >= target)
            minlen = mid;
        else
            maxlen = mid;
    }
    cout << fixed << setprecision(2) << floor(maxlen*100)/100.0 << endl;
//    printf("%.2lf\n", floor(maxlen*100)/100);
//  以上两种写法都可以AC，但是注意表达式内不要写mid，要写maxlen
//  最后如果是mid=1.999，保留两位，直接是1.99
//  maxlen是2.001,直接保留2.00
    return 0;
}

/**
 * @description: poj1064 数字放大100倍做法,输入浮点数分成整数部分和小数部分，避免1.50输入后变成1.4999999
 * @author: michael ming
 * @date: 2019/5/2 20:00
 * @modified by: 
 */
#include <iostream>
using namespace std;
int main()
{
    int cables, target, cable_we_get;
    cin >> cables >> target;
    int minlen = 1, maxlen = 10000000, mid, len[10001], ans;
    int int_part, float_part;
    char ch;
    for(int i = 0; i < cables; ++i)
    {
        cin >> int_part >> ch >> float_part;
        len[i] = int_part * 100 + float_part;
    }
    while(maxlen - minlen >= 0)
    {
        cable_we_get = 0;
        mid = minlen + (maxlen - minlen)/2;
        for(int i = 0; i < cables; ++i)
        {
            cable_we_get += len[i]/mid;
        }
        if(cable_we_get >= target)
            minlen = mid+1;
        else
            maxlen = mid-1;
    }
    cout << maxlen/100 << "." << (maxlen/10)%10 << maxlen%10 << endl;
    return 0;
}