添加动态规划

Author: wangjieCode

动态规划/dynamic.js

@@ -0,0 +1,52 @@
+// 有3种硬币面值分别为 2， 5,7
+// 给定目标27，求使用最少的组合搭配出27
+// 7 7 7 + 2 2 2 ==》 6
+
+const dp = {}
+const findMinNums = (x) => {
+    if (dp[x]) return dp[x]
+    if (x <= 0) return x;
+    let res = Number.MAX_VALUE;
+    if (x >= 2) {
+        res = Math.min(res, findMinNums(x - 2) + 1)
+    }
+    if (x >= 5) {
+        res = Math.min(res, findMinNums(x - 5) + 1)
+    }
+    if (x >= 7) {
+        res = Math.min(res, findMinNums(x - 7) + 1)
+    }
+    dp[x] = res
+    return res
+}
+const findMinNums2 = (A, x) => {
+    const dp = [];
+    dp[0] = 0;
+    for(let i = 1; i < x; i ++){
+        dp[i] = Number.MAX_VALUE
+        for(let j = 0; j < A.length; j ++){
+            if( i < A[j] ||  dp[ i - A[j] ] == Number.MAX_VALUE) continue;
+            dp[i] = Math.min(dp[i], dp[ i - A[j] ] + 1)
+        }
+    }
+    return dp[x - 1 ]
+}
+
+function test(m, n) {
+    const dp = [];
+    dp[0] = [1];
+    for (let i = 0; i < m; i++) {
+        for (let j = 0; j < n; i++) {
+            if (i === 0 || j === 0) {
+                console.log(dp[i],i,j)
+                dp[i][j] = 1;
+            }
+            else dp[i][j] = dp[i - 1][j] + dp[i][j - 1];
+        }
+    }
+
+    return dp[m - 1][n - 1]
+}
+console.time()
+console.log(findMinNums2([2,5,7],27))
+console.timeEnd()