init commit

contests/1contest/3.cpp

@@ -0,0 +1,36 @@
+#include <iostream>
+#include <string>
+#include <cctype>
+
+int main() {
+    int c;
+    c = getchar();
+
+    bool is_num = false;
+
+    while (c != EOF) {
+        if (c == '0' && !is_num) {
+            int old = c;
+            c = getchar();
+
+            if (!(c == EOF || !isdigit(c))) {
+                continue;
+            }
+
+            putchar(old);
+        } else if (isdigit(c)) {
+            is_num = true;
+        } else {
+            is_num = false;
+        }
+
+        putchar(c);
+        c = getchar();
+    }
+
+    if (c != '\n') {
+        putchar('\n');
+    }
+
+    return 0;
+}