feat: 最大正方形

sl1673495 · sl1673495 · commit f95e194e3210 · 2020-06-27T01:52:29.000+08:00
diff --git a/动态规划/恢复空格-面试题 17.13.js b/动态规划/恢复空格-面试题 17.13.js
@@ -16,4 +16,4 @@ let respace = function (dictionary, sentence) {
     dp[i] = min
   }
   return dp[n]
-}
+}
diff --git a/动态规划/最大正方形-221.js b/动态规划/最大正方形-221.js
@@ -0,0 +1,44 @@
+/**
+ * @param {character[][]} matrix
+ * @return {number}
+ */
+let maximalSquare = function (matrix) {
+  let maxY = matrix.length
+  if (!maxY) return 0
+  let maxX = matrix[0].length
+
+  let dp = []
+  let max = 0
+
+  let dpBasic = (y, x) => {
+    if (matrix[y][x] === "1") {
+      max = 1
+      dp[y][x] = 1
+    } else {
+      dp[y][x] = 0
+    }
+  }
+  for (let y = 0; y < maxY; y++) {
+    dp[y] = []
+    dpBasic(y, 0)
+  }
+  for (let x = 1; x < maxX; x++) {
+    dpBasic(0, x)
+  }
+
+  for (let y = 1; y < maxY; y++) {
+    for (let x = 1; x < maxX; x++) {
+      let val = matrix[y][x]
+      if (val === "0") {
+        dp[y][x] = 0
+      } else {
+        let left = dp[y][x - 1]
+        let top = dp[y - 1][x]
+        let leftTop = dp[y - 1][x - 1]
+        dp[y][x] = Math.min(left, top, leftTop) + 1
+        max = Math.max(max, dp[y][x])
+      }
+    }
+  }
+  return max * max
+}

Original file line number	Diff line number	Diff line change
`@@ -16,4 +16,4 @@ let respace = function (dictionary, sentence) {`
`16`	`16`	`dp[i] = min`
`17`	`17`	`}`
`18`	`18`	`return dp[n]`
`19`		`-}`
	`19`	`+}`