Merge pull request #1262 from laerpeeK/master

Update 背包理论基础01背包JavaScript代码块

problems/背包理论基础01背包-1.md

@@ -380,28 +380,37 @@ func main() {
 ### javascript 
 
 ```js
-function testweightbagproblem (wight, value, size) {
-  const len = wight.length, 
-    dp = array.from({length: len + 1}).map(
-      () => array(size + 1).fill(0)
-    );
-  
-  for(let i = 1; i <= len; i++) {
-    for(let j = 0; j <= size; j++) {
-      if(wight[i - 1] <= j) {
-        dp[i][j] = math.max(
-          dp[i - 1][j], 
-          value[i - 1] + dp[i - 1][j - wight[i - 1]]
-        )
-      } else {
-        dp[i][j] = dp[i - 1][j];
-      }
-    }
-  }
+/**
+ * 
+ * @param {Number []} weight 
+ * @param {Number []} value 
+ * @param {Number} size 
+ * @returns 
+ */
 
-//   console.table(dp);
+function testWeightBagProblem(weight, value, size) {
+const len = weight.length,
+dp = Array.from({length: len}).map(
+() => Array(size + 1))  //JavaScript 数组是引用类型	
+for(let i = 0; i < len; i++) {  //初始化最左一列，即背包容量为0时的情况
+dp[i][0] = 0;
+}
+for(let j = 1; j < size+1; j++) { //初始化第0行, 只有一件物品的情况
+if(weight[0] <= j) {
+dp[0][j] = value[0];
+} else {
+dp[0][j] = 0;
+}
+}
+	
+for(let i = 1; i < len; i++) {  //dp[i][j]由其左上方元素推导得出
+for(let j = 1; j < size+1; j++) {
+if(j < weight[i]) dp[i][j] = dp[i - 1][j];
+else dp[i][j] = Math.max(dp[i-1][j], dp[i-1][j - weight[i]] + value[i]);
+}
+}
 
-  return dp[len][size];
+return dp[len-1][size] //满足条件的最大值
 }
 
 function testWeightBagProblem2 (wight, value, size) {