diff --git a/OnlineJudges/lydsy/1789.cpp b/OnlineJudges/lydsy/1789.cpp
new file mode 100644
index 0000000..f943ad3
--- /dev/null
+++ b/OnlineJudges/lydsy/1789.cpp
@@ -0,0 +1,19 @@
+#include <cstdio>
+inline int min(int a, int b) { return a < b ? a : b; }
+int l[3], lcp, ans, sum;
+char s[3][60];
+int main()
+{
+    scanf("%d%s%d%s%d%s", &l[0], s[0], &l[1], s[1], &l[2], s[2]);
+    ans = sum = l[0] + l[1] + l[2];
+    while (lcp < min(l[0], min(l[1], l[2])) && s[0][lcp] == s[1][lcp] && s[1][lcp] == s[2][lcp]) lcp++;
+    for (int i = 0; i < 3; i++)
+        for (int j = i + 1; j < 3; j++)
+        {
+            int lcp2 = lcp;
+            while (lcp2 < min(l[i], l[j]) && s[i][lcp2] == s[j][lcp2]) lcp2++;
+            ans = min(ans, (l[i] - lcp2) + (l[j] - lcp2) + (sum - l[i] - l[j] - lcp) + (lcp2 - lcp));
+        }
+    printf("%d", ans);
+    return 0;
+}
\ No newline at end of file
diff --git a/OnlineJudges/lydsy/1830.cpp b/OnlineJudges/lydsy/1830.cpp
new file mode 100644
index 0000000..f943ad3
--- /dev/null
+++ b/OnlineJudges/lydsy/1830.cpp
@@ -0,0 +1,19 @@
+#include <cstdio>
+inline int min(int a, int b) { return a < b ? a : b; }
+int l[3], lcp, ans, sum;
+char s[3][60];
+int main()
+{
+    scanf("%d%s%d%s%d%s", &l[0], s[0], &l[1], s[1], &l[2], s[2]);
+    ans = sum = l[0] + l[1] + l[2];
+    while (lcp < min(l[0], min(l[1], l[2])) && s[0][lcp] == s[1][lcp] && s[1][lcp] == s[2][lcp]) lcp++;
+    for (int i = 0; i < 3; i++)
+        for (int j = i + 1; j < 3; j++)
+        {
+            int lcp2 = lcp;
+            while (lcp2 < min(l[i], l[j]) && s[i][lcp2] == s[j][lcp2]) lcp2++;
+            ans = min(ans, (l[i] - lcp2) + (l[j] - lcp2) + (sum - l[i] - l[j] - lcp) + (lcp2 - lcp));
+        }
+    printf("%d", ans);
+    return 0;
+}
\ No newline at end of file