C - Get an Even String

https://codeforces.com/contest/1660/submission/151572746

CodeForces/1660/C/C.cpp

@@ -0,0 +1,44 @@
+#include <algorithm>
+#include <cstring>
+#include <iostream>
+#include <string>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+const int N = 2e5 + 5;
+
+int t, ans, f[N][2], pre[N], last[N];
+std::string s;
+
+int main() {
+    std::ios::sync_with_stdio(false);
+
+    cin >> t;
+    while (t--) {
+        ans = 0;
+        memset(f, 0x00, sizeof(f));
+        memset(last, 0x00, sizeof(last));
+
+        cin >> s;
+        s = ' ' + s;
+
+        for (int i = 1; i < s.size(); i++) {
+            pre[i] = last[s[i] - 'a'];
+            last[s[i] - 'a'] = i;
+        }
+
+        for (int i = 1; i < s.size(); i++) {
+            f[i][0] = std::max(f[i - 1][0], f[i - 1][1]);
+            if (pre[i]) {
+                f[i][1] = f[pre[i]][0] + 2;
+            }
+            ans = std::max({ans, f[i][0], f[i][1]});
+        }
+
+        cout << s.size() - ans - 1 << endl;
+    }
+
+    return 0;
+}