프로그래머스 C++ Lv.2 퍼즐게임 (PCCP 기출문제 2번)

https://school.programmers.co.kr/learn/courses/30/lessons/340212

프로그래머스

 

 

이분탐색 쓸 생각 못했었는데 적용하는 계기가 되었다.

 

#include <string>
#include <vector>
#include <iostream>
#include <algorithm>

using namespace std;

bool Possiblelevel(int level, vector<int> diffs, vector<int> times, long long limit)
{
    long long time_cur = times[0], time_prev = 0;
    long long result = 0;
    for (int i = 0; i < diffs.size(); i++)
    {
        if (i != 0)
        {
            time_cur = times[i];
            time_prev = times[i-1];
        }
        long long repetition = diffs[i]- level;
        if (repetition > 0)
        {
            result += (time_cur + time_prev) * repetition + time_cur;
        } else
        {
            result += time_cur;
        }
    }
    if (result > limit) return false;
    return true;
}


long long solution(vector<int> diffs, vector<int> times, long long limit) {
    
    long long left = 1, right = diffs[0];
    for (int i = 0; i < diffs.size(); i++)
    {
        if (right < diffs[i])
            right = diffs[i];
    }
    while (left <= right)
    {
        long long mid = (left + right) / 2;
        if (Possiblelevel(mid, diffs, times, limit))
        {
            right = mid - 1;
        } else {
            left = mid + 1;
        }
    }

    return left;
}