Reference

• https://unagi-zoso.tistory.com/63
• https://stackoverflow.com/questions/45551241/where-is-the-performance-gain-of-the-erase-remove-idiom-coming-from

결과

• true: Erase-remove Idiom 사용
  • Elapsed time: 1162ms
• false: Erase-remove Idiom 비사용
  • Elapsed time: 1871ms

비교코드

• solve(true)를 하면 eraseRemoveIdiom을 사용한 것이고, false라면 사용하지 않은 것.

#include <iostream>
#include <string>
#include <list>
#include <algorithm>
#include <vector>
#include <time.h>
using namespace std;

#undef DEBUG
#ifdef DEBUG
#define DEBUG_MSG(str) do {std::cout << str;} while(false)
#else
#define DEBUG_MSG(str) do {  } while( false )
#endif


int solve(int N, bool useEraseRemoveIdiom){
    // cout<<__cplusplus<<endl;
    vector<int> v;
	for (int i = 0; i < N; i++) {
		v.push_back(i);
	}
	DEBUG_MSG("지우기 전:          " << endl);
    DEBUG_MSG("v.size(): " << v.size() << endl);
	for (int i = 0; i < v.size(); i++) {
		DEBUG_MSG(v[i] << " ");
	}
	DEBUG_MSG(endl);

    auto logical_end = remove_if(v.begin(), v.end(), [](int i) { return i % 2 == 0; });
    if(useEraseRemoveIdiom){
        v.erase(logical_end, v.end());
    }else{
        for(int i=N-1; i>=0; --i){
            if(v[i] % 2 == 0){
                v.erase(v.begin() + i);
            }
        }
    }

	DEBUG_MSG("5번 인덱스 지운 후: " << endl);
    DEBUG_MSG("v.size(): " << v.size() << endl);
	for (int i = 0; i < v.size(); i++) {
		DEBUG_MSG(v[i] << " ");
	}
	DEBUG_MSG(endl);
}

int main() {
    ios_base::sync_with_stdio(0);
	cin.tie(0);
    time_t start = clock();
    // solve(10000, false);
	solve(10000, true);
    cout << "Elapsed time: " << clock() - start << "ms" << endl;
	return 0;
}

사용컴파일러버전: g++20,