update Top-K(add heap solution)

biaodigit · biaodigit · commit 3b02c52b9140 · 2018-11-11T12:51:37.000+08:00
diff --git a/Classical algorithm problem/KMP.html b/Classical algorithm problem/KMP.html
@@ -13,17 +13,16 @@
             while (j > -1 && str[j + 1] !== str[i]) {
                 j = next[j]
             }
-            if (str[j + 1] === str[i]) {
+            if (str[i] === str[j + 1]) {
                 j++
             }
             next[i] = j
         }
-    };
+    }
 
     function kmp(str, pstr) {
         let slen = str.length,
             plen = pstr.length,
-            i = 0,
             j = -1,
             next = new Array(plen),
             res = [];
@@ -35,15 +34,15 @@
             if (str[i] === pstr[j + 1]) {
                 j++
             }
-            if(j === plen - 1){
+            if (j === plen - 1) {
                 res.push(i - j);
                 j = -1
             }
         }
         return res.length ? res : 0
     }
 
-    console.log(kmp("bacbababadababacambabacaddababacasdsd", "ababaca"))
+    console.log(kmp("bbc abcdab abcdababacde", "ababac"))
 </script>
 </body>
 </html>
diff --git a/Classical algorithm problem/Top K.html b/Classical algorithm problem/Top K.html
@@ -10,14 +10,26 @@
      * 以求top k大为例
      * @param arr
      */
-    //region bf解法
     function topK(arr, k) {
-        let index = bfprt(arr, 0, arr.length - 1, k),
-            res = arr.slice(0, index + 1);
-        console.log(`原数组：${arr}`);
-        console.log(`前${k}大元素：${res}`)
+        let bfArr = arr.slice(0),
+            heapArr = arr.slice(0);
+        //bf solution
+        let bfindex = bfprt(arr, 0, bfArr.length - 1, k),
+            ret1 = arr.slice(0, bfindex + 1);
+
+        console.log(`bf solution: 前${k}大元素：${ret1}`);
+
+        //heap solution
+        let heap = new indexMaxHeap(heapArr),
+            ret2 = [];
+        for (let i = 0; i < k; i++) {
+            ret2.push(heap.extractMax())
+        }
+        console.log(`heap solution: 前${k}大元素：${ret2}`)
+
     }
 
+    //region bf solution
     let bfprt = function (arr, l, r, k) {
         let central_index = getCentralIndex(arr, l, r),
             boundary_index = partition(arr, l, r, central_index),
@@ -75,6 +87,67 @@
     };
     //endregion
 
+    //region heap solution
+    class indexMaxHeap {
+        constructor(arr) {
+            this.data = [];
+            this.indexes = [];
+            this.reverse = [];
+            this.count = 0;
+            for (let i = 0; i < arr.length; i++) {
+                this.insert(i, arr[i])
+            }
+
+        }
+
+        insert(i, value) {
+            this.data[++i] = value;
+            this.indexes[++this.count] = i;
+            this.reverse[i] = this.count;
+            this.shiftUp(this.count)
+
+        }
+
+        shiftUp(k) {
+            while (k > 1 && this.data[this.indexes[k]] > this.data[this.indexes[k >> 1]]) {
+                this.swapIndex(k, k >> 1)
+                k = k >> 1
+            }
+        }
+
+        shiftDown(k) {
+            while (2 * k <= this.count) {
+                let j = 2 * k;
+                if (j + 1 <= this.count - 1 && this.data[this.indexes[j + 1]] > this.data[this.indexes[j]]) {
+                    j += 1;
+                }
+                if (this.data[this.indexes[k]] >= this.data[this.indexes[j]]) return;
+
+                this.swapIndex(k, j)
+                k = j;
+            }
+        }
+
+        extractMax() {
+            let res = this.data[this.indexes[1]];
+            this.swapIndex(1, this.count);
+            this.reverse[this.indexes[this.count]] = 0;
+            this.count--;
+            this.shiftDown(1);
+            return res
+        }
+
+        swapIndex(i, j) {
+            [this.indexes[i], this.indexes[j]] = [this.indexes[j], this.indexes[i]]
+
+            this.reverse[this.indexes[i]] = i;
+            this.reverse[this.indexes[j]] = j
+
+        }
+    }
+
+    //endregion
+
     topK([32, 153, 100, -50, -10, 6, 5, 1356, 20, 160, 2, 1432, 4, 50, 14, 102, -30, 3, 45, 1312, 1, -1, -3], 7)
 </script>
 </body>

Original file line number	Diff line number	Diff line change
`@@ -13,17 +13,16 @@`
`13`	`13`	`while (j > -1 && str[j + 1] !== str[i]) {`
`14`	`14`	`j = next[j]`
`15`	`15`	`}`
`16`		`- if (str[j + 1] === str[i]) {`
	`16`	`+ if (str[i] === str[j + 1]) {`
`17`	`17`	`j++`
`18`	`18`	`}`
`19`	`19`	`next[i] = j`
`20`	`20`	`}`
`21`		`- };`
	`21`	`+ }`
`22`	`22`
`23`	`23`	`function kmp(str, pstr) {`
`24`	`24`	`let slen = str.length,`
`25`	`25`	`plen = pstr.length,`
`26`		`- i = 0,`
`27`	`26`	`j = -1,`
`28`	`27`	`next = new Array(plen),`
`29`	`28`	`res = [];`
`@@ -35,15 +34,15 @@`
`35`	`34`	`if (str[i] === pstr[j + 1]) {`
`36`	`35`	`j++`
`37`	`36`	`}`
`38`		`- if(j === plen - 1){`
	`37`	`+ if (j === plen - 1) {`
`39`	`38`	`res.push(i - j);`
`40`	`39`	`j = -1`
`41`	`40`	`}`
`42`	`41`	`}`
`43`	`42`	`return res.length ? res : 0`
`44`	`43`	`}`
`45`	`44`
`46`		`- console.log(kmp("bacbababadababacambabacaddababacasdsd", "ababaca"))`
	`45`	`+ console.log(kmp("bbc abcdab abcdababacde", "ababac"))`
`47`	`46`	`</script>`
`48`	`47`	`</body>`
`49`	`48`	`</html>`