6868
6969<!-- 这里可写通用的实现逻辑 -->
7070
71- 哈希表实现。
71+ ** 方法一:位运算**
72+ 73+ 我们可以用一个长度为 10ドル$ 的数组 $mask$ 来表示每根杆上的环的颜色情况,其中 $mask[ i] $ 表示第 $i$ 根杆上的环的颜色情况,如果第 $i$ 根杆上有红色、绿色、蓝色的环,那么 $mask[ i] $ 的二进制表示为 111ドル,ドル即 $mask[ i] = 7$。
74+ 75+ 我们遍历字符串 $rings,ドル对于每个颜色位置对 $(c, j),ドル其中 $c$ 表示环的颜色,$j$ 表示环所在的杆的编号,我们将 $mask[ j] $ 对应的二进制位进行置位,即 $mask[ j] |= d[ c] ,ドル其中 $d[ c] $ 表示颜色 $c$ 对应的二进制位。
76+ 77+ 最后我们统计 $mask$ 中值为 7ドル$ 的元素的个数,即为集齐全部三种颜色环的杆的数目。
78+ 79+ 时间复杂度 $O(n),ドル空间复杂度 $O(|\Sigma|),ドル其中 $n$ 表示字符串 $rings$ 的长度,而 $|\Sigma|$ 表示字符集的大小。
7280
7381<!-- tabs:start -->
7482
7987``` python
8088class Solution :
8189 def countPoints (self rings : str ) -> int :
82- mp = defaultdict(set )
83- for i in range (1 , len (rings), 2 ):
84- c = int (rings[i])
85- mp[c].add(rings[i - 1 ])
86- return sum (len (v) == 3 for v in mp.values())
90+ mask = [0 ] * 10
91+ d = {" R" 1 , " G" 2 , " B" 4 }
92+ for i in range (0 , len (rings), 2 ):
93+ c = rings[i]
94+ j = int (rings[i + 1 ])
95+ mask[j] |= d[c]
96+ return mask.count(7 )
8797```
8898
8999### ** Java**
@@ -93,14 +103,19 @@ class Solution:
93103``` java
94104class Solution {
95105 public int countPoints (String rings ) {
96- Map<Integer , Set<Character > > mp = new HashMap<> ();
97- for (int i = 1 ; i < rings. length(); i += 2 ) {
98- int c = rings. charAt(i) - ' 0'
99- mp. computeIfAbsent(c, k - > new HashSet<> ()). add(rings. charAt(i - 1 ));
106+ int [] d = new int [' Z'
107+ d[' R' = 1 ;
108+ d[' G' = 2 ;
109+ d[' B' = 4 ;
110+ int [] mask = new int [10 ];
111+ for (int i = 0 , n = rings. length(); i < n; i += 2 ) {
112+ int c = rings. charAt(i);
113+ int j = rings. charAt(i + 1 ) - ' 0'
114+ mask[j] |= d[c];
100115 }
101116 int ans = 0 ;
102- for (Set< Character > e : mp . values() ) {
103- if (e . size() == 3 ) {
117+ for (int x : mask ) {
118+ if (x == 7 ) {
104119 ++ ans;
105120 }
106121 }
@@ -115,54 +130,54 @@ class Solution {
115130class Solution {
116131public:
117132 int countPoints(string rings) {
118- unordered_map<int, unordered_set<char >> mp;
119- for (int i = 1; i < rings.size(); i += 2) {
120- int c = rings[ i] - '0';
121- mp[ c] .insert(rings[ i - 1] );
133+ int d[ 'Z'] {[ 'R'] = 1, [ 'G'] = 2, [ 'B'] = 4};
134+ int mask[ 10] {};
135+ for (int i = 0, n = rings.size(); i < n; i += 2) {
136+ int c = rings[ i] ;
137+ int j = rings[ i + 1] - '0';
138+ mask[ j] |= d[ c] ;
122139 }
123- int ans = 0;
124- for (int i = 0; i < 10; ++i)
125- if (mp[ i] .size() == 3)
126- ++ans;
127- return ans;
140+ return count(mask, mask + 10, 7);
128141 }
129142};
130143```
131144
132145### **Go**
133146
134147```go
135- func countPoints(rings string) int {
136- mp := make(map[byte]map[byte]bool)
137- for i := 1; i < len(rings); i += 2 {
148+ func countPoints(rings string) (ans int) {
149+ d := ['Z']int{'R': 1, 'G': 2, 'B': 4}
150+ mask := [10]int{}
151+ for i, n := 0, len(rings); i < n; i += 2 {
138152 c := rings[i]
139- if len(mp[c]) == 0 {
140- mp[c] = make(map[byte]bool)
141- }
142- mp[c][rings[i-1]] = true
153+ j := int(rings[i+1] - '0')
154+ mask[j] |= d[c]
143155 }
144- ans := 0
145- for _, v := range mp {
146- if len(v) == 3 {
156+ for _, x := range mask {
157+ if x == 7 {
147158 ans++
148159 }
149160 }
150- return ans
161+ return
151162}
152163```
153164
154165### ** TypeScript**
155166
156167``` ts
157168function countPoints(rings : string ): number {
158- const = (c : string ) => c .charCodeAt (0 ) - ' A' charCodeAt (0 );
159- const = rings .length ;
160- const = (1 << helper (' R' + (1 << helper (' G' + (1 << helper (' B'
161- const = new Array (10 ).fill (0 );
162- for (let i = 0 ; i < n ; i += 2 ) {
163- count [rings [i + 1 ]] |= 1 << helper (rings [i ]);
169+ const = (c : string ) => c .charCodeAt (0 ) - ' A' charCodeAt (0 );
170+ const : number [] = Array (26 ).fill (0 );
171+ d [idx (' R' = 1 ;
172+ d [idx (' G' = 2 ;
173+ d [idx (' B' = 4 ;
174+ const : number [] = Array (10 ).fill (0 );
175+ for (let i = 0 ; i < rings .length ; i += 2 ) {
176+ const = rings [i ];
177+ const = rings [i + 1 ].charCodeAt (0 ) - ' 0' charCodeAt (0 );
178+ mask [j ] |= d [idx (c )];
164179 }
165- return count . reduce (( r , v ) => ( r += v === target ? 1 : 0 ), 0 ) ;
180+ return mask . filter ( x => x === 7 ). length ;
166181}
167182```
168183
@@ -171,16 +186,22 @@ function countPoints(rings: string): number {
171186``` rust
172187impl Solution {
173188 pub fn count_points (rings : String ) -> i32 {
174- let rings = rings . as_bytes ();
175- let target = (1 << b 'R'- b 'A'+ (1 << b 'G'- b 'A'+ (1 << b 'B'- b 'A'
176- let n = rings . len ();
177- let mut count = [0 ; 10 ];
178- let mut i = 0 ;
179- while i < n {
180- count [(rings [i + 1 ] - b '0'as usize ] |= 1 << rings [i ] - b 'A'
181- i += 2 ;
189+ let mut d : [i32 ; 90 ] = [0 ; 90 ];
190+ d ['R' as usize ] = 1 ;
191+ d ['G' as usize ] = 2 ;
192+ d ['B' as usize ] = 4 ;
193+ 194+ let mut mask : [i32 ; 10 ] = [0 ; 10 ];
195+ 196+ let cs : Vec <char > = rings . chars (). collect ();
197+ 198+ for i in (0 .. cs . len ()). step_by (2 ) {
199+ let c = cs [i ] as usize ;
200+ let j = cs [i + 1 ] as usize - '0' as usize ;
201+ mask [j ] |= d [c ];
182202 }
183- count . iter (). filter (| & v | * v == target ). count () as i32
203+ 204+ mask . iter (). filter (|&& x | x == 7 ). count () as i32
184205 }
185206}
186207```
@@ -189,17 +210,28 @@ impl Solution {
189210
190211``` c
191212int countPoints (char* rings) {
192- int target = (1 << ('R' - 'A')) + (1 << ('G' - 'A')) + (1 << ('B' - 'A'));
193- int count[ 10] = {0};
194- for (int i = 0; rings[ i] ; i += 2) {
195- count[ rings[ i + 1] - '0'] |= 1 << (rings[ i] - 'A');
213+ int d[ 'Z'] ;
214+ memset(d, 0, sizeof(d));
215+ d[ 'R'] = 1;
216+ d[ 'G'] = 2;
217+ d[ 'B'] = 4;
218+ 219+ int mask[10];
220+ memset(mask, 0, sizeof(mask));
221+ 222+ for (int i = 0, n = strlen(rings); i < n; i += 2) {
223+ int c = rings[i];
224+ int j = rings[i + 1] - '0';
225+ mask[j] |= d[c];
196226 }
227+ 197228 int ans = 0;
198229 for (int i = 0; i < 10; i++) {
199- if (count [ i] == target ) {
230+ if (mask [i] == 7 ) {
200231 ans++;
201232 }
202233 }
234+ 203235 return ans;
204236}
205237```
0 commit comments