iOS 最优路径算法
=== 路径规划 ===
我们有一个有向无环图，权重在节点上。
需求：从一个起点开始，找到一条节点权重之和最大的最优路径。
输入: n个节点，m个路径，起点
输出: 最优路径的权重值之和
举例:
3个节点与权重: A=1, B=2, C=2
3条路径: A->B, B->C, A->C
起点: A
输出: 5 (最优路径是 A->B->C ， 权重之和是 1+2+2=5)
NodeModel.h
#import
NS_ASSUME_NONNULL_BEGIN
@interface NodeModel : NSObject
@property (nonatomic, copy) NSString *node;
@property (nonatomic, assign) NSInteger index;
@property (nonatomic, assign) NSInteger value;
-(void)currentValueAndIndex:(NSString *)node;
@end
NS_ASSUME_NONNULL_END
NodeModel.m
#import "NodeModel.h"
@implementation NodeModel
-(void)currentValueAndIndex:(NSString *)node{
_node = node;
if ([_node isEqualToString:@"A"]) {
_value = 0;
}else if ([_node isEqualToString:@"B"]) {
_value = 10;
}else if ([_node isEqualToString:@"C"]) {
_value = 3;
}else if ([_node isEqualToString:@"D"]) {
_value = 4;
}else if ([_node isEqualToString:@"E"]) {
_value = 5;
}else if ([_node isEqualToString:@"F"]) {
_value = 20;
}else if ([_node isEqualToString:@"G"]) {
_value = 7;
}else if ([_node isEqualToString:@"H"]) {
_value = 80;
}else if ([_node isEqualToString:@"I"]) {
_value = 9;
}
if ([_node isEqualToString:@"A"]) {
_index = 0;
}else if ([_node isEqualToString:@"B"]) {
_index = 1;
}else if ([_node isEqualToString:@"C"]) {
_index = 2;
}else if ([_node isEqualToString:@"D"]) {
_index = 3;
}else if ([_node isEqualToString:@"E"]) {
_index = 4;
}else if ([_node isEqualToString:@"F"]) {
_index = 5;
}else if ([_node isEqualToString:@"G"]) {
_index = 6;
}else if ([_node isEqualToString:@"H"]) {
_index = 7;
}else if ([_node isEqualToString:@"I"]) {
_index = 8;
}
}
@end
viewController中：
-(void)routePlanning{
NSMutableArray *nodeArray = [@[@"A", @"B", @"D", @"D", @"C", @"F", @"F", @"H", @"A"]copy];
NSMutableArray *array = [NSMutableArray array];
NSMutableDictionary *allDic = [NSMutableDictionary dictionary];
for (int i = 0; i NodeModel *model = [[NodeModel alloc]init]; model.node = [nodeArray objectAtIndex:i]; [model currentValueAndIndex:model.node]; [array addObject:model]; } [array sortUsingComparator:^NSComparisonResult(NodeModel *obj1, NodeModel *obj2) { return obj1.index > obj2.index; }]; [self search:array allDic:allDic]; NSNumber *max = [allDic.allKeys valueForKeyPath:@"@max.floatValue"]; NSLog(@"%@",max); NSArray *resultArray = [allDic valueForKey:[NSString stringWithFormat:@"%@",max]]; [resultArray enumerateObjectsUsingBlock:^(NodeModel *obj, NSUInteger idx, BOOL * _Nonnull stop) { NSLog(@"%@ %ld %ld",obj.node,obj.index,obj.value); }]; } -(void)search:(NSMutableArray *)array allDic:(NSMutableDictionary *)allDic{ for (int i = 0; i NSMutableArray *sortArray = [NSMutableArray array]; /** 存储搜索后的model集合 */ NodeModel *lastModel = [array objectAtIndex:i]; NSMutableArray *nextArray = [[NSMutableArray arrayWithArray:array]mutableCopy]; [nextArray removeObject:lastModel]; /** 去重，减少循环次数 */ if (sortArray.count) { NSMutableSet *nextSet = [NSMutableSet setWithArray:nextArray]; NSMutableSet *sortSet = [NSMutableSet setWithArray:sortArray]; [nextSet minusSet:sortSet]; nextArray = [nextSet.allObjects mutableCopy]; } NodeModel *finalModel; NodeModel *currentModel; for (int j = 0; j currentModel = [nextArray objectAtIndex:j]; if (!(currentModel.value > lastModel.value && currentModel.index > lastModel.index)) { continue; } if (sortArray.count == 0) { [sortArray addObject:lastModel]; finalModel = currentModel; [sortArray addObject:finalModel]; } /** 判断是否在左侧与右侧的范围 */ BOOL isLeftRange = currentModel.value >= lastModel.value && currentModel.index >= lastModel.index && currentModel.value <= finalModel.value && currentModel.index <= finalModel.index; /** 判断是否大于最右侧的范围 */ BOOL isRightRange = currentModel.value > finalModel.value && currentModel.index > finalModel.index; if (isRightRange) { if (![sortArray containsObject:finalModel]) { [sortArray addObject:finalModel]; } if (![sortArray containsObject:currentModel]) { [sortArray addObject:currentModel]; } lastModel = finalModel; finalModel = currentModel; continue; } if (isLeftRange) { if (![sortArray containsObject:lastModel]) { [sortArray addObject:lastModel]; } if (![sortArray containsObject:currentModel]) { [sortArray addObject:currentModel]; } if (sortArray.count == 2) { lastModel = sortArray.firstObject; }else{ lastModel = currentModel; } continue; } } __block NSInteger sum = 0; [sortArray enumerateObjectsUsingBlock:^(NodeModel *obj, NSUInteger idx, BOOL * _Nonnull stop) { sum = sum + obj.value; }]; [allDic setValue:sortArray forKey:[NSString stringWithFormat:@"%ld",sum]]; } }