常用算法OC实现

1. 希尔排序

    - (void)shellSort:(NSMutableArray *)array {
    
    NSInteger i,j,gap;
    NSInteger n = array.count;
    for (gap = n/2; gap > 0; gap/=2) {
        for (i=gap; i=0 && [array[j] integerValue] > [array[j +gap] integerValue]; j -= gap) {
                [array exchangeObjectAtIndex:j withObjectAtIndex:j+gap];
            }
        }
    }
    }

2. 快速排序

快排
- (void)quickSort:(NSMutableArray *)array count:(NSInteger)count{
    
    [self __quickSort:array left:0 right:count-1];
}

- (void)__quickSort:(NSMutableArray *)array left:(NSInteger)l right:(NSInteger )r{
    if (l>=r) {
        return;
    }
    NSInteger p = [self __partition:array left:l right:r];
    [self __quickSort:array left:l right:p-1];
    [self __quickSort:array left:p+1 right:r];
}

- (NSInteger )__partition:(NSMutableArray *)array left:(NSInteger)l right:(NSInteger )r{
    [array exchangeObjectAtIndex:l withObjectAtIndex:(random()%(r-l+1))+l];
    NSInteger v = [array[l] integerValue];
    NSInteger j = l;
    for (NSInteger i = l+1; i

3. 直接插入排序

- (void)insertSort:(NSMutableArray *)array{
NSInteger i,j,temp;
NSInteger n = array.count;
for (i = 1; i=0&&[array[j] integerValue] > temp; j--) {
            array[j +1] = array[j];
        }
        array[j+1] = @(temp);
    }
}
}

/// 插入排序2
- (void)insertSort:(NSMutableArray *)array count:(NSInteger)count{
    for (NSInteger i = 1; i < count; i++) {
        NSInteger j = i;
        for ( j = i; j>0; j--) {
            if ([array[i] integerValue] < [array[j-1] integerValue]) {
//                [array exchangeObjectAtIndex:j withObjectAtIndex:j-1];
                array[j] = array[j-1];
            }else{
                /// 比前面的都大 不处理 直接结束遍历
                break;
            }
        }
        array[j] = array[i];
    }
}

4. 简单选择排序

- (void)selectedSort:(NSMutableArray *)array{

NSInteger i,j,min;
NSInteger n = array.count;
for (i=0; i

5. 冒泡排序

- (void)bubbleSort:(NSMutableArray *)array{
NSInteger i,j;
NSInteger n = array.count;
BOOL flag = YES;
for (i = 0; ii; j--) {
        if ([array[j] integerValue] < [array[j-1] integerValue]) {
            [array exchangeObjectAtIndex:j withObjectAtIndex:j-1];
            flag = YES;
        }
    }
}
}

6. 归并排序

// 归并排序 自底向上
- (void)mergeSortBU:(NSMutableArray *)array count:(NSInteger)count{
    
    for (NSInteger sz = 1; sz <=count; sz+=sz) {
        for (NSInteger i =0; i= r) {
        return;
    }
//    NSInteger mid = (l+r)/2;
    NSInteger mid = l + (r-l)/2;
    [self __mergeSort:array left:l right:mid];
    [self __mergeSort:array left:mid+1 right:r];
///  由于数组的左边和右边都已经排好序了，这时候如果左边的最大值 小于右边的最小值那说明 已经排好序了 不需要在排序了
    if ([array[mid] integerValue] > [array[mid +1] integerValue]) {
        [self __merge:array left:l midle:mid right:r];
    }

}

/// [l...mid]   [mid+1.....r]  进行合并
- (void)__merge:(NSMutableArray *)array left:(NSInteger)l midle:(NSInteger)mid right:(NSInteger )r{
    
    NSMutableArray *tempArray = [NSMutableArray array];
    for (NSInteger i = l; i<=r; i++) {
        tempArray[i-l] = array[i];
    }
    NSInteger i=l ,j = mid +1;
    
    for (NSInteger k = l; k<=r; k++) {
        if (i >mid) {
            array[k] = tempArray[j-l];
            j++;
        }else if(j>r){
            array[k] = tempArray[i-l];
            i++;
        }else if ([tempArray[i-l] integerValue] < [tempArray[j-l] integerValue]) {
            array[k] = tempArray[i-l];
            i++;
        }else {
            array[k] = tempArray[j-l];
            j++;
        }
    }
}