fix: p97 subtract panic.

src/problem/p97_interleaving_string.rs

@@ -10,28 +10,32 @@ impl Solution {
     pub fn is_interleave(s1: String, s2: String, s3: String) -> bool {
         let (s1, s2, s3): (Vec<char>, Vec<char>, Vec<char>) = (s1.chars().collect(), s2.chars().collect(), s3.chars().collect());
         let (n, m, t) = (s1.len(), s2.len(), s3.len());
-        
+
         if n + m != t {
             return false;
         }
-        
+
         let mut dp = vec![false; m + 1];
         dp[0] = true;
-        
+
         for i in 0..=n {
             for j in 0..=m {
+                if i == 0 && j == 0 {
+                    continue;
+                }
+
                 let p = i + j - 1;
-                
+
                 if i != 0 {
                     dp[j] &= s1[i - 1] == s3[p];
                 }
-                
+
                 if j != 0 {
                     dp[j] |= dp[j - 1] && s2[j - 1] == s3[p];
                 }
             }
         }
-        
+
         dp[m]
     }
 }
@@ -44,5 +48,6 @@ mod tests {
 
     #[test]
     fn test_97() {
+        assert!(Solution::is_interleave("aabcc".to_owned(), "dbbca".to_owned(), "aadbbcbcac".to_owned()));
     }
 }