Added 0473-matchsticks-to-square.rs

rust/0179-largest-number.rs

@@ -0,0 +1,20 @@
+use std::cmp::Ordering;
+
+impl Solution {
+    pub fn largest_number(nums: Vec<i32>) -> String {
+        let mut ans = String::new();
+        let mut nums = nums;
+        let mut strs = nums.into_iter().map(|e| e.to_string()).collect::<Vec<String>>();
+        strs.sort_by(|a, b| {
+            let a_first = a.clone() + &*b;
+            let b_first = b.clone() + &*a;
+            b_first.cmp(&a_first)
+        });
+        for num in strs {
+            if ans == "0" && num == "0" {continue}
+            ans.push_str(&*num.to_string())
+        }
+
+        ans
+    }
+}

rust/0473-matchsticks-to-square.rs

@@ -0,0 +1,36 @@
+impl Solution {
+    pub fn makesquare(matchsticks: Vec<i32>) -> bool {
+        fn backtrack(
+            sides: &mut [i64; 4],
+            matches: &Vec<i32>,
+            idx: usize,
+            length: i64
+        ) -> bool {
+            if idx >= matches.len() {
+                return true
+            }
+
+            for i in 0..4 {
+                if sides[i] + matches[idx] as i64 <= length {
+                    sides[i] += matches[idx] as i64;
+                    if backtrack(sides, matches, idx + 1, length) {
+                        return true
+                    }
+                    sides[i] -= matches[idx] as i64
+                }
+            }
+            false
+        }
+
+        let mut total = 0;
+        for mat in matchsticks.iter() {
+            total += *mat as i64;
+        }
+        let mut matchsticks = matchsticks;
+        matchsticks.sort_by_key(|e| std::cmp::Reverse(*w));
+
+        let side = total / 4;
+
+        backtrack(&mut [0, 0, 0, 0], &matchsticks, 0, side)
+    }
+}