二分查找

来源：互联网发布：靠谱的淘宝代购编辑：程序博客网时间：2024/06/14 04:16

一、函数的调用

- (void)clicked {    NSArray *arrayNumbers = @[@-4,@-2,@4,@6,@9,@14,@23,@100];    NSInteger res = [self searchValue:arrayNumbers num:15];    NSInteger ress = [self searchValueIndex:arrayNumbers num:100 low:0 hight:[arrayNumbers count]];    NSLog(@"Chenfy--:%d",ress);}

二、函数的实现

//迭代- (NSInteger)searchValue:(NSArray *)arrayValue num:(NSInteger)num {    int low = 0,hight = [arrayValue count] - 1,mid;    while (!(low > hight)) {        mid = ((low + hight)/2);        NSInteger value = [arrayValue[mid] integerValue];        if (value == num) {            return mid;        }        if (value > num) {            hight = mid - 1;        } else {            low = mid + 1;        }    }    return -1;}//递归- (NSInteger)searchValueIndex:(NSArray *)arrayValue num:(NSInteger)num low:(NSInteger)low hight:(NSInteger)hight {    if (low > hight) {        return -1;    }    NSInteger mid = (low + hight)/2;    NSInteger value = [arrayValue[mid] integerValue];    if (value == num) {        return mid;    }    if (value > num) {        return [self searchValueIndex:arrayValue num:num low:low hight:mid - 1];    } else {        return [self searchValueIndex:arrayValue num:num low:mid + 1 hight:hight];    }    return -1;}

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