Number that appears in the array more than half

Description:

There is a number in the array that appears more than half the length of the array. Please find this number. For example, enter an array {, 2} with a length of 9 }. Because number 2 appears five times in the array and exceeds half the length of the array, Output 2.

 

Input:

Each test case contains two rows:

Enter an integer N (1 <=n <= 100000) In the first line, indicating the number of elements in the array.

In the second line, enter n integers, indicating each element in the array. The range of these N integers is [1,].

 

Output:

For each test case, the number of output times exceeds half of the length of the array. If-1 is not output.

 

Sample input:

91 2 3 2 2 2 5 4 2

Sample output:

2

 1 #include <stdio.h> 2 void main() 3 { 4     int n; 5     while(scanf("%d",&n)!=EOF) 6     { 7         int array[100000]; 8         for (int i=0; i< n; i++) 9         {10             scanf("%d",&array[i]);11         }12         int result = array[0];13         int times = 1;14         i = 0;15         while(i < n)16         {17             if (times == 0)18             {19                 result = array[i];20                 times = 1;21             }22             if (result == array[i])23                 times++;24             else25                 times--;26             i++;27         }28         int count =0;29         for (int j=0; j < n; j++)30         {31             if(array[j]  == result)32                 count++;33         }34         if (2*count > n)35             printf("%d\n",result);36         else37             printf("-1\n");38     }39 }

Another methord

 1 #include <stdio.h> 2  3 int partition(int array[], int start, int end) 4 { 5     int key = array[start]; 6     while(start < end) 7     { 8         while(start<end && array[end]>=key) end--; 9         if (start<end)10         {11             array[start] = array[end];12             start++;13         }14         else15         {16             break;17         }18 19         while(start <end && array[start] < key) start++;20         if (start < end)21         {22             array[end] = array[start];23             end--;24         }25     }26     array[start] = key;27     return start;28 }29 30 int checkMoreHalf(int array[],int lenght,int number)31 {32     int total = 0;33     for (int i=0; i<lenght; i++)34     {35         if (array[i] == number)36             total++;37     }38     if (2*total > lenght)39     {40         return 1;41     }42     return -1;43 }44 45 void MoreThanHalfNum(int array[], int length)46 {47     int middle = length >> 1;48     int start  = 0;49     int end    = length -1;50     int index = partition(array,start,end);51     while(index != middle)52     {53         if (index > middle)54         {55             end = index -1;56         }57         else58         {59             start = index+1;60         }61         index = partition(array,start,end);62     }63     if (checkMoreHalf(array,length,array[index]) == 1)64     {65         printf("%d\n",array[index]);66     }67     else68     {69         printf("-1\n");70     }71 }72 73 void main()74 {75     int n;76     while(scanf("%d",&n)!=EOF)77     {78         int array[100000];79         for (int i=0; i< n; i++)80         {81             scanf("%d",&array[i]);82         }83         MoreThanHalfNum(array,n);84     }85 }

 

Number that appears in the array more than half