/****************************************************************** find the biggest x number in a sequence* the basic method is the same as the QuickSort** 1. move the smaller one before the pivot* 2. move the bigger one after the pivot* 3. determin whether the X matches the pivot's index* 3.1 if y return the index* 3.2 if n recursively call the func with proper param* *****************************************************************/#define cnt 10#include <stdio.h>#include <stdlib.h>#include <string.h>#include <time.h>
int findBiggestX(int* pa, int low, int high, int key);
int main(void){
int arr[cnt]; int i=0; int key = 4; printf("arr is :\n"); srand((unsigned)time(NULL));//use current time as seed for(i=0;i<cnt;i++) { arr[i]=rand()%100; printf("%d\t",arr[i]); } printf("\n\n");
findBiggestX(arr,0,sizeof(arr)/sizeof(int)-1,key); for(i=0;i<cnt;i++) { printf("%d\t",arr[i]); } printf("\n"); for(i=0;i<key;i++) { printf("%d\t",arr[i]); } printf("\n"); getchar(); return 0;}
int findBiggestX(int* pa, int low, int high, int key){ int pivot = pa[0]; int low_temp = low; int high_temp = high; while(low<high) { while(pa[high]>=pivot && low<high) { high--; } pa[low]=pa[high]; while(pa[low]<=pivot && low<high) { low++; } pa[high]=pa[low]; } pa[low]=pivot; if(key-1 == low) { return low; } else if(key-1 < low) { return findBiggestX(pa,low_temp,low,key); } else { return findBiggestX(pa,low+1,high_temp,key); }}
转载于:https://www.cnblogs.com/warnet/p/3825803.html
