二分查找

#include <stdio.h>
#include <string.h>
typedef struct {
    int hash;
    char data[20];
} D;


int search(int* nums, int numsSize, int target) {
    int left=0;
    int right=numsSize;
    int mid;
    while(left<right){
        mid=(right+left)/2;
        if(nums[mid]==target){return mid;}
        else if(nums[mid]<target){left=mid+1;}
        else if(nums[mid]>target){right=mid;}
    }
    return -1;
}

int searchB(D *d, int size, D target){
    int left = 0;
    int right = size;
    int mid;
    int i;
    while(left<right){
        mid = (right+left)/2;
        if(d[mid].hash == target.hash){
            if(0==strcmp(d[mid].data,target.data)){return mid;}

            
            for(left=1;d[mid-left].hash == target.hash;left++){
                if(0==strcmp(d[mid-left].data,target.data)){return mid-left;}
            }
            
            for(right=1;d[mid+right].hash == target.hash;right++){
                if(0==strcmp(d[mid+right].data,target.data)){return mid+right;}
            }
            return -1;
        }
        else if(d[mid].hash<target.hash){left=mid+1;}
        else if(d[mid].hash>target.hash){right=mid;}
    }

    return -1;

}





int main()
{
    D d[10];
    int i;
    for (i=0;i<10;i++)
    {
        d[i].hash=i;
        sprintf(d[i].data,"PPPPP  %d",i);
    }
    d[7].hash = 6;
    d[8].hash = 6; 
    d[5].hash = 6; 

    for (i=0;i<10;i++)
    {
        printf("%d -> %d\t%s\n",i,d[i].hash,d[i].data);
    }

    D f = {6,"PPPPP  8"};
    
    int r = searchB(d,10,f);
    printf("r = %d\n",r);

    return 0;
}