vector 中删除指定元素(个数为1-n个)

删除有两种方式

方法1: 直接使用vector中的erase删除:

方法2: 利用STL提供的算法 -> erase-remove (此种方法效率较高)



两种方法效率对比:

#include <algorithm>

#include <iostream>

#include <vector>

#include <algorithm>

#include <time.h>

#include <Windows.h>

using namespace std;



#define COUNT 1000000

typedef std::vector<int> IntVec;

typedef IntVec::iterator IntVec_It;

int main()

{

IntVec intVec1;

IntVec intVec2;

for (int i = 0;i < COUNT;i++)

{

intVec1.push_back(i);

intVec2.push_back(i);

}

for (int i = 100;i < 300;i++)

{

intVec1[i] = 20;

intVec2[i] = 20;

}

for (int i = 700;i < 1000;i++)

{

intVec1[i] = 20;

intVec2[i] = 20;

}

clock_t t1 = clock();

intVec1.erase(std::remove(intVec1.begin(),intVec1.end(),20),intVec1.end());

IntVec_It it1 = std::find(intVec1.begin(),intVec1.end(),20);

if (it1 != intVec1.end())

cout << "intVec1 -----" << endl;

clock_t t2 = clock();

cout << "lgorithm1 cost = " << t2-t1 << endl;

clock_t t3 = clock();

for (IntVec_It it = intVec2.begin();it != intVec2.end();)

{

if (*it == 20)

it = intVec2.erase(it);

else

it++;

}

IntVec_It it2 = std::find(intVec2.begin(),intVec2.end(),20);

if (it2 != intVec2.end())

cout << "intVec2 ----" << endl;

clock_t t4 = clock();

cout << "lgorithm2 cost = " << t4-t3 << endl;

return 0;

}