Objective-C学习笔记－第一天(3)

话不多说，学了这么多，写个快速排序先。

除了快排，以后有时间还要加堆排、归并等等。

今天学了有，类、协议、语法。

因为算法类，不止一个算法。所以新建一个Algorithm(算法)协议：

 #import <Foundation/Foundation.h>

 @protocol AlgorithmProtocol <NSObject>

 @optional
 +(void)quickSortWithArray:(NSMutableArray*)array FirstIndex:(long)first EndIndex:(long)end CompareMethod:(bool(^)(id,id)) compare;

 @end

接下来，新建一个Algorithm(算法)类，遵循算法协议：

 #import <Foundation/Foundation.h>
 #import "AlgorithmProtocol.h"

 @interface Algorithm : NSObject <AlgorithmProtocol>

 @end

 @implementation Algorithm

 +(void)quickSortWithArray:(NSMutableArray*)array FirstIndex:(long)firstIndex EndIndex:(long)endIndex CompareMethod:(bool(^)(id,id)) compare{
     long (^partition)(NSMutableArray*,long,long) = ^(NSMutableArray *innerArray,long first,long end){
         long i = first;
         long j = end;
         while (i<j) {
             while (i<j && !compare(innerArray[i],innerArray[j])) {
                 j--;
             }
             if (i<j) {
                 id tmp = innerArray[i];
                 innerArray[i] = innerArray[j];
                 innerArray[j] = tmp;
                 i++;
             }
             while (i<j && !compare(innerArray[i],innerArray[j])) {
                 i++;
             }
             if (i<j) {
                 id tmp = innerArray[i];
                 innerArray[i] = innerArray[j];
                 innerArray[j] = tmp;
                 j--;
             }
         }
         return i;
     };
     if (firstIndex<endIndex) {
         long pivot = ;
         pivot = partition(array,firstIndex,endIndex);
         [self quickSortWithArray:array FirstIndex:firstIndex EndIndex:pivot- CompareMethod:compare];
         [self quickSortWithArray:array FirstIndex:pivot+ EndIndex:endIndex CompareMethod:compare];
     }
 }

 @end

然后就是使用，main文件：

#import <Foundation/Foundation.h>
#import "Algorithm.h"

int main(int argc, const char * argv[]) {
    @autoreleasepool {
        //测试数组
        NSMutableArray *array = [[NSMutableArray alloc] init];
        [array addObject:@];
        [array addObject:@];
        [array addObject:@];
        [array addObject:@];
        [array addObject:@];
        NSMutableArray *arrayCopy = [array copy];

        [Algorithm quickSortWithArray:array FirstIndex: EndIndex:[array count] -  CompareMethod:^bool(id obj1, id obj2) {
            if (obj1>obj2){
                return true;
            }else{
                return false;
            }
        }];

        NSLog(@"\n排序前:%@\n排序后：%@",arrayCopy,array);
    }
    return ;
}

验证一下结果：