NSTimeTnterval 用法系统排序,冒泡排序,选择排序比较

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//性能比较: 系统排序速度最快,冒泡排序和选择排序时间差不多, 但同样比系统慢很多很多

//排序次数少不太明显, 次数多就显现出来了

//NSLog(@"��系统排序��");

NSTimeInterval aTimer =0;

for (int i =0; i < 10000; i++) {

NSDate *date1 = [NSDate date];

NSMutableArray *array = [NSMutableArray arrayWithObjects:@"v",@"f", @"a",@"c", @"w",nil];

[array sortedArrayUsingSelector:@selector(compare:)];

NSDate *date2 = [NSDate date];

aTimer = [date2 timeIntervalSinceDate:date1] *1000; // 毫秒数要乘以1000, 本身得到的是秒数

}

NSLog(@"♻️♻️♻️系统排序所用时间:毫秒数: %f", aTimer);

//NSLog(@"��冒泡排序��");

NSTimeInterval aTimer2 =0;

for (int i =0; i < 10000; i++) {

NSDate *date3 = [NSDate date];

NSMutableArray *array2 = [NSMutableArray arrayWithObjects:@"v",@"f", @"a",@"c", @"w",nil];

int count = (int)[array2 count];

for (int i =0; i < count - 1; i++) {

for (int j =0; j < count - 1 - i; j++) {

if ([array2[j] compare:array2[j + 1]] > 0) {

[array2 exchangeObjectAtIndex:j withObjectAtIndex:j +1];

}

NSDate *date4 = [NSDate date];

aTimer2 = [date4 timeIntervalSinceDate:date3] *1000;

}

NSLog(@"♻️♻️♻️冒泡排序所用时间:毫秒数: %f", aTimer2);

//NSLog(@"��选择排序��");

NSTimeInterval aTimer3 =0;

for (int i =0; i < 10000; i++) {

NSDate *date5 = [NSDate date];

NSMutableArray *array3 = [NSMutableArray arrayWithObjects:@"v",@"f", @"a",@"c", @"w",nil];

int count3 = (int)[array3 count], min =0;

for (int i =0; i < count3 - 1; i++) {

min = i;

for (int j =0; j < count3 - 1 - i; j++) {

if ([array3[j] compare:array3[j + 1]] > 0) {

min = j;

}

if (min != i) {

[array3 exchangeObjectAtIndex:i withObjectAtIndex:min];

}

NSDate *date6 = [NSDate date];

aTimer3 = [date6 timeIntervalSinceDate:date5] *1000;

}

NSLog(@"♻️♻️♻️选择排序所用时间:毫秒数: %f", aTimer3);

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