leetcode-1/src/majorityElement/majorityElement.cpp at master · daction/leetcode-1 · GitHub

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// Source : https://oj.leetcode.com/problems/majority-element/

// Author : Hao Chen

// Date : 2014-12-25

/**********************************************************************************

* Given an array of size n, find the majority element. The majority element is the element that appears more than ⌊ n/2 ⌋ times.

* You may assume that the array is non-empty and the majority element always exist in the array.

* Credits:Special thanks to @ts for adding this problem and creating all test cases.

**********************************************************************************/

#include <stdlib.h>

#include <iostream>

#include <vector>

#include <string>

#include <sstream>

using namespace std;

// Moore Voting Algorithm

// Refer to:

// http://www.cs.utexas.edu/~moore/best-ideas/mjrty/index.html

int majorityElement(vector<int> &num) {

int majority;

int cnt = 0;

for(int i=0; i<num.size(); i++){

if ( cnt ==0 ){

majority = num[i];

cnt++;

}else{

majority == num[i] ? cnt++ : cnt --;

if (cnt >= num.size()/2+1) return majority;

}

return majority;

}

vector<int> &split(const string &s, char delim, vector<int> &elems) {

stringstream ss(s);

string item;

while (getline(ss, item, delim)) {

elems.push_back(atoi(item.c_str()));

}

return elems;

}

vector<int> split(const string &s, char delim) {

vector<int> elems;

split(s, delim, elems);

return elems;

}

int main(int argc, char** argv)

{

string array = "1,2,1,2,1,2,1,2,1,2,1";

if (argc > 1){

array = argv[1];

}

cout << "[" << array << "]" << endl;

vector<int> num = split(array, ',');

cout << majorityElement(num) <<endl;

return 0;

}

leetcode-1/src/majorityElement/majorityElement.cpp at master · daction/leetcode-1 · GitHub

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