Create 1667_wyg1997.cpp

NBUTOJ/1667_wyg1997.cpp

@@ -0,0 +1,80 @@
+#include <cstdio>
+#include <cstring>
+#include <algorithm>
+using namespace std;
+struct node
+{
+	int from,to;
+	int l;
+}data[100011];
+int main()
+{
+	int u;
+	int n;
+	int num;
+	int a[100011];
+	int ans;
+	scanf ("%d",&u);
+	while (u--)
+	{
+		scanf ("%d",&n);
+		for (int i = 1 ; i <= n ; i++)
+			scanf ("%d",&a[i]);
+		num = 1;
+		ans = 1;
+		data[num].from = 1;
+		data[num].l = 1;
+		for (int i = 2 ; i <= n ; i++)
+		{
+			if (a[i] > a[i-1])
+			{
+				data[num].l++;
+				data[num].to = i;
+				ans = max (ans,data[num].l);
+			}
+			else
+			{
+				num++;
+				data[num].from = i;
+				data[num].to = i;
+				data[num].l = 1;
+			}
+		}
+		if (ans == n || ans == n-1)		//特判一下
+		{
+			printf ("%d\n",n);
+			continue;
+		}
+//		if (ans == n - 1)		//题目不清晰，不知道是否可以把该数改为负数 
+//		{
+//			if ((a[1] < a[2]) || (a[1] >= a[2] && a[2] != 0))
+//				printf ("%d\n",n);
+//			else
+//				printf ("%d\n",ans);
+//			continue;
+//		}
+		ans++;
+		for (int i = 1 ; i < num ; i++)
+		{
+			if (data[i+1].l == 1 || data[i].l == 1)		//子串长度为1挺麻烦的，单独处理下 
+			{
+				ans = max (ans , data[i+1].l + 1);
+				ans = max (ans , data[i].l + 1);
+				if (data[i+1].l == 1 && i != num-1)
+				{
+					if (a[data[i+1].to-1] + 1 < a[data[i+2].from])
+						ans = max (ans , data[i].l + data[i+2].l + 1);
+				}
+			}
+			else
+			{
+				if (a[data[i].to-1] + 1 < a[data[i+1].from])		//修改前一个子串的最后一个数 
+					ans = max (ans , data[i].l + data[i+1].l);
+				if (a[data[i+1].from-1] + 1 < a[data[i+1].from+1])		//修改后一个子串的第一个数 
+					ans = max (ans , data[i].l + data[i+1].l);
+			}
+		}
+		printf ("%d\n",ans);
+	}
+	return 0;
+}