Objective-C學習筆記－第一天(3)

標籤：

話不多說，學了這麼多，寫個快速排序先。

除了快排，以後有時間還要加堆排、歸併等等。

今天學了有，類、協議、文法。

因為演算法類，不止一個演算法。所以建立一個Algorithm(演算法)協議：

1 #import <Foundation/Foundation.h>2 3 @protocol AlgorithmProtocol <NSObject>4 5 @optional6 +(void)quickSortWithArray:(NSMutableArray*)array FirstIndex:(long)first EndIndex:(long)end CompareMethod:(bool(^)(id,id)) compare;7 8 @end

接下來，建立一個Algorithm(演算法)類，遵循演算法協議：

 1 #import <Foundation/Foundation.h> 2 #import "AlgorithmProtocol.h" 3  4 @interface Algorithm : NSObject <AlgorithmProtocol> 5  6 @end 7  8 @implementation Algorithm 9 10 +(void)quickSortWithArray:(NSMutableArray*)array FirstIndex:(long)firstIndex EndIndex:(long)endIndex CompareMethod:(bool(^)(id,id)) compare{11     long (^partition)(NSMutableArray*,long,long) = ^(NSMutableArray *innerArray,long first,long end){12         long i = first;13         long j = end;14         while (i<j) {15             while (i<j && !compare(innerArray[i],innerArray[j])) {16                 j--;17             }18             if (i<j) {19                 id tmp = innerArray[i];20                 innerArray[i] = innerArray[j];21                 innerArray[j] = tmp;22                 i++;23             }24             while (i<j && !compare(innerArray[i],innerArray[j])) {25                 i++;26             }27             if (i<j) {28                 id tmp = innerArray[i];29                 innerArray[i] = innerArray[j];30                 innerArray[j] = tmp;31                 j--;32             }33         }34         return i;35     };36     if (firstIndex<endIndex) {37         long pivot = 0;38         pivot = partition(array,firstIndex,endIndex);39         [self quickSortWithArray:array FirstIndex:firstIndex EndIndex:pivot-1 CompareMethod:compare];40         [self quickSortWithArray:array FirstIndex:pivot+1 EndIndex:endIndex CompareMethod:compare];41     }42 }43 44 @end

然後就是使用，main檔案：

#import <Foundation/Foundation.h>#import "Algorithm.h"int main(int argc, const char * argv[]) {    @autoreleasepool {        //測試數組        NSMutableArray *array = [[NSMutableArray alloc] init];        [array addObject:@12];        [array addObject:@2];        [array addObject:@33];        [array addObject:@4];        [array addObject:@54];        NSMutableArray *arrayCopy = [array copy];                [Algorithm quickSortWithArray:array FirstIndex:0 EndIndex:[array count] - 1 CompareMethod:^bool(id obj1, id obj2) {            if (obj1>obj2){                return true;            }else{                return false;            }        }];                NSLog(@"\n排序前:%@\n排序後：%@",arrayCopy,array);    }    return 0;}

驗證一下結果：

 

Objective-C學習筆記－第一天(3)