修复可能越界的bug

janestar · May 26, 2014 · 86ecfee · 86ecfee
1 parent ebb384b
commit 86ecfee
Showing 1 changed file with 2 additions and 2 deletions.
diff --git a/C++/chapDFS.tex b/C++/chapDFS.tex
@@ -63,7 +63,7 @@ \subsubsection{深搜1}
     }
 
     bool isPalindrome(const string &s, int start, int end) {
-        while (s[start] == s[end]) {
+        while (start < end && s[start] == s[end]) {
             ++start;
             --end;
         }
@@ -101,7 +101,7 @@ \subsubsection{深搜2}
         }
     }
     bool isPalindrome(const string &s, int start, int end) {
-        while (s[start] == s[end]) {
+        while (start < end && s[start] == s[end]) {
             ++start;
             --end;
         }