Merge pull request #2111 from fwqaaq/patch-29

Update 0279.完全平方数.md about Rust

problems/0279.完全平方数.md

@@ -356,6 +356,7 @@ var numSquares2 = function(n) {
 TypeScript：
 
 ```typescript
+// 先遍历物品
 function numSquares(n: number): number {
     const goodsNum: number = Math.floor(Math.sqrt(n));
     const dp: number[] = new Array(n + 1).fill(Infinity);
@@ -370,6 +371,64 @@ function numSquares(n: number): number {
 };
 ```
 
+```rust
+// 先遍历背包
+function numSquares(n: number): number {
+  const dp = Array(n + 1).fill(Infinity)
+  dp[0] = 0;
+  for(let i = 1; i <= n; i++){
+      for(let j = 1; j * j <= i; j++){
+          dp[i] = Math.min(dp[i], dp[i -j * j] + 1)
+      }
+  }
+  return dp[n]
+};
+```
+
+Rust:
+
+```rust
+// 先遍历背包
+impl Solution {
+    pub fn num_squares(n: i32) -> i32 {
+        let n = n as usize;
+        let mut dp = vec![i32::MAX; n + 1];
+        dp[0] = 0;
+        for i in 0..=n {
+            let mut j = 1;
+            loop {
+                match j * j > i {
+                    true => break,
+                    false => dp[i] = dp[i].min(dp[i - j * j] + 1),
+                }
+                j += 1;
+            }
+        }
+        dp[n]
+    }
+}
+```
+
+```rust
+// 先遍历物品
+impl Solution {
+    pub fn num_squares(n: i32) -> i32 {
+        let (n, mut goods) = (n as usize, 1);
+        let mut dp = vec![i32::MAX; n + 1];
+        dp[0] = 0;
+        loop {
+            if goods * goods > n {
+                break;
+            }
+            for j in goods * goods..=n {
+                dp[j] = dp[j].min(dp[j - goods * goods] + 1);
+            }
+            goods += 1;
+        }
+        dp[n]
+    }
+}
+```
 
 
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