438. 找到字符串中所有字母异位词

test009.cpp

@@ -0,0 +1,29 @@
+class Solution {
+public:
+    bool checkCnt(vector<int>& cnts, vector<int>& cntp){
+        for(int i = 0; i < 26; i++){
+            if(cnts[i] != cntp[i]) return false;
+        }
+        return true;
+    }
+    vector<int> findAnagrams(string s, string p) {
+        vector<int> cntp(26);
+        for(char c:p){ cntp[c-'a']++; }
+        
+        vector<int> ret;
+        vector<int> cnts(26);
+        for(int i = 0; i < min(p.length(), s.length()); i++){ 
+            cnts[s[i] - 'a']++; 
+        }
+
+        if(checkCnt(cnts, cntp)) { ret.push_back(0);}
+
+        for(int r = p.length(); r < s.length(); r++){
+            int l = r - p.length() + 1;
+            cnts[s[l-1] - 'a']--;
+            cnts[s[r] - 'a']++;
+            if(checkCnt(cnts, cntp)) { ret.push_back(l); }
+        }
+        return ret;
+    }
+};