[Heap] backjoon-1927

Author: Seogeurim

src/Heap/P1927/Main.java

@@ -0,0 +1,91 @@
+package Heap.P1927;
+
+import java.io.BufferedReader;
+import java.io.FileInputStream;
+import java.io.InputStreamReader;
+import java.util.ArrayList;
+import java.util.List;
+
+public class Main {
+
+    static int N, x;
+    static MinHeap heap;
+
+    public static void main(String[] args) throws Exception{
+//        System.setIn(new FileInputStream("src/Heap/P1927/input.txt"));
+
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        N = Integer.parseInt(br.readLine());
+
+        heap = new MinHeap();
+        for (int i = 0; i < N; i++) {
+            x = Integer.parseInt(br.readLine());
+            if (x == 0) System.out.println(heap.remove());
+            else heap.insert(x);
+//            System.out.println(heap.toString());
+        }
+    }
+}
+
+class MinHeap {
+    List<Integer> heap;
+
+    public MinHeap() {
+        this.heap = new ArrayList<>();
+        heap.add(0);
+    }
+
+    public void insert(int value){
+        heap.add(value);
+        int current = heap.size() - 1;
+        int parent = current / 2;
+
+        while (parent != 0 && heap.get(parent) > heap.get(current)) {
+            int temp = heap.get(parent);
+            heap.set(parent, heap.get(current));
+            heap.set(current, temp);
+
+            current = parent;
+            parent = current / 2;
+        }
+    }
+
+    public int remove(){
+        if (heap.size() == 1)
+            return 0;
+
+        int top = heap.get(1);
+        heap.set(1, heap.get(heap.size() - 1));
+        heap.remove(heap.size() - 1);
+
+        int current = 1;
+        while (true) {
+            int left = current * 2;
+            if (left >= heap.size()){
+                break;
+            }
+
+            int targetIdx = left;
+            int right = current * 2 + 1;
+            if (right < heap.size() && heap.get(right) < heap.get(targetIdx)){
+                targetIdx = right;
+            }
+
+            if (heap.get(targetIdx) < heap.get(current)){
+                int temp = heap.get(current);
+                heap.set(current, heap.get(targetIdx));
+                heap.set(targetIdx, temp);
+                current = targetIdx;
+            } else {
+                break;
+            }
+        }
+
+        return top;
+    }
+
+    @Override
+    public String toString() {
+        return "MinHeap{" + heap + "}";
+    }
+}

src/Heap/P1927/input.txt

@@ -0,0 +1,32 @@
+31
+4
+15
+11
+20
+13
+19
+23
+3
+24
+99
+193
+1
+3
+483
+213
+0
+0
+0
+0
+0
+0
+0
+0
+0
+0
+0
+0
+0
+0
+0
+0