p5

1 files changed, 59 insertions, 0 deletions

diff --git a/src/bin/p0005.rs b/src/bin/p0005.rs
new file mode 100644
index 0000000..ce4d5e4
--- /dev/null
+++ b/src/bin/p0005.rs
@@ -0,0 +1,59 @@
+impl Solution {
+    pub fn check_palindrome_len(s: &String, i: i32) -> (i32, i32, i32) {
+        let mut r = 0;
+        loop {
+            let next = r + 1;
+            if i - next < 0
+                    || i + next >= s.len() as i32
+                    || s.as_bytes()[(i-next) as usize] != s.as_bytes()[(i+next) as usize] {
+                break;
+            }
+            r = next;
+        }
+        let len1 = 2 * r + 1;
+        let start1 = i - r;
+        let end1 = i + r;
+
+        r = 0;
+        loop {
+            let next = r + 1;
+            if i - next + 1 < 0
+                || i + next >= s.len() as i32
+                || s.as_bytes()[(i-next+1) as usize] != s.as_bytes()[(i+next) as usize] {
+                break;
+            }
+            r = next;
+        }
+        let len2 = 2 * r;
+        let start2 = i - r + 1;
+        let end2 = i + r;
+
+        if len2 > len1 {
+            (len2, start2, end2)
+        } else {
+            (len1, start1, end1)
+        }
+    }
+
+    pub fn longest_palindrome(s: String) -> String {
+        let mut maxpalinlen = -1;
+        let mut start: i32 = 0;
+        let mut end: i32 = 0;
+        for i in 0..s.len() {
+            let (palin_len, pstart, pend) = Self::check_palindrome_len(&s, i as i32);
+            if palin_len > maxpalinlen {
+                maxpalinlen = palin_len;
+                start = pstart;
+                end = pend;
+            }
+        }
+        s[start as usize ..(end + 1) as usize].to_string()
+    }
+}
+
+struct Solution {}
+
+fn main () {
+    println!("{}", Solution::longest_palindrome("babad".to_string()));
+    println!("{}", Solution::longest_palindrome("cbbd".to_string()));
+}
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