[구창민] sprint12

algorithm/sorts.js

@@ -0,0 +1,101 @@
+function selectionSort(arr){
+    const result = arr;
+    const n = arr.length;
+    for(let i=0;i<n-1;i++){
+        let minIndex = i;
+        for(let j=i+1;j<n;j++){
+            if(result[minIndex]>result[j]){
+                minIndex = j;
+            }
+        }
+     if(minIndex !== i){
+        let temp = result[i];
+        result[i] = result[minIndex];
+        result[minIndex] = temp;
+     }
+    }
+    return result;
+}
+function insertionSort(arr){
+    for(let i=1;i<arr.length;i++){
+        let current  = arr[i];
+        let j=0;
+        for(j=i-1;j>=0 && arr[j]>current;j--){
+            arr[j+1] = arr[j];
+        }
+        arr[j+1]=current;
+    }
+}
+function mergeSort(arr){
+    if(arr.length<=1){
+        return arr;
+    }
+
+    const mid = Math.floor(arr.length/2);
+    const left = arr.slice(0,mid);
+    const right= arr.slice(mid);
+
+    const sortedLeft = mergeSort(left);
+    const sortedRight = mergeSort(right);
+
+    return merge(sortedLeft,sortedRight);
+}
+
+function merge(left,right){
+    const result = [];
+    let i=0;
+    let j=0;
+
+    while(i<left.length && j<right.length){
+        if(left[i] <= right[j]){
+            result.push(left[i]);
+            i++;
+        }else{
+            result.push(right[j]);
+            j++;
+        }
+    }
+
+    result.push(...left.slice(i));
+    result.push(...right.slice(j));
+    return result;
+}
+
+function quickSort(arr,start=0,end=null){
+    if(end === null){
+        end = arr.length -1;
+    }
+
+    if(start <end){
+        const pivot = partition(arr,start,end);
+        quickSort(arr,start,pivot -1);
+        quickSort(arr,pivot+1,end);
+    }
+}
+function partition(arr,start,end){
+    const pivot = arr[end];
+    let i = start -1;
+
+    for(let j=start;j<end;j++){
+        if(arr[j]<=pivot){
+            i++;
+            [arr[i],arr[j]]=[arr[j],arr[i]];
+        }
+    }
+    [arr[i+1],arr[end]] = [arr[end],arr[i+1]];
+    return i+1;
+}
+const nums = [8,4,6,2,5];
+console.log(nums); 
+selectionSort(nums);
+console.log(nums); 
+
+
+insertionSort(nums);
+console.log(nums); 
+
+console.log(mergeSort(nums));
+
+quickSort(nums);
+console.log(nums); 
+