huaweibishi

java/bishi/HeChangDui.java

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+import java.io.BufferedReader;
+import java.io.InputStreamReader;
+
+public class HeChangDui {
+
+    public static void main(String[] args) throws Exception {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+
+        String str;
+        while ((str = br.readLine()) != null) {
+            int total = Integer.parseInt(str);
+            int[] data = new int[total];
+            int[] reverseData = new int[total];
+            // 处理身高数据
+            str = br.readLine();
+            String[] arr = str.split(" ");
+
+            for (int i = 0; i < total; ++i) {
+                data[i] = Integer.parseInt(arr[i]);
+                reverseData[total - 1 - i] = data[i];
+            }
+
+            int[] asc = calculate(data);
+            int[] desc = calculate(reverseData);
+            int ret = 0;
+            for (int i = 1; i <= total; i++) {
+                ret = Math.max(asc[i] + desc[total - i + 1] - 1, ret);
+            }
+
+            System.out.println(total - ret);
+        }
+    }
+
+    private static int[] calculate(int[] data) { // max[i]存储最长子序列长度为i的时候,最小的序列结尾.
+        int total = data.length;
+        int[] max = new int[total];
+        int[] dp = new int[total + 1];
+        int index = 0;
+        max[index] = -1;
+        for (int i = 0; i < total; i++) {
+            if (data[i] > max[index]) {
+                max[++index] = data[i];
+                dp[i + 1] = dp[i] + 1;
+            } else {
+                for (int j = 0; j <= index; j++) { // 因为i的循环顺序是从小到大的,所以保证了当max[j]的数都是在i之前按序列顺序先后出现的.
+                    if (data[i] <= max[j]) {
+                        max[j] = data[i];
+                        break;
+                    }
+                }
+                dp[i + 1] = dp[i];
+            }
+        }
+
+        return dp;
+    }
+}