01:59(160)

migrate/migrate.cpp

@@ -1,16 +1,36 @@
 #include<bits/stdc++.h>
 using namespace std;
 int c, t;
-int n, d;
-int x[2000005];
+int n;
+long long d;
+long long x[2000005];
+long long fa[5005][5005];
 int main() {
     freopen("migrate.in", "r", stdin);
     freopen("migrate.out", "w", stdout);
     scanf("%d%d", &c, &t);
     while(t--) {
-        scanf("%d%d", &n, &d);
+        scanf("%d%lld", &n, &d);
         for(int i = 1; i <= n; ++i) {
-            scanf("%d", &x[i]);
+            scanf("%lld", &x[i]);
+        }
+        if(c <= 10) {
+            long long ans = 0;
+            for(int i = 1; i < n; ++i) {
+                fa[i][i] = 1;
+                fa[i][i + 1] = (x[i + 1] - x[i] <= d) && (fa[x + 2] - x[i]) > d;
+            }
+            fa[n][n] = 1;
+            for(int len = 2; len <= n; ++len) {
+                for(int l = 1; l + len - 1 <= n; ++l) {
+                    int r = l + len - 1;
+                    for(int mid = l; mid <= r - 1; ++mid) {
+                        fa[l][r] += fa[l][mid] * fa[mid + 1][r];
+                    }
+                    if(fa[l][r] == 2) ans++;
+                }
+            }
+            printf("%lld\n", ans);
         }
     }
     return 0;
@@ -20,4 +40,5 @@ g++ migrate/migrate.cpp -o migrate/migrate -std=c++14 -O2 -static -Wall && cp mi
 
 每次飞行长度不超过 d
 体力消耗为飞行次数
+长度最短一定不回溯
 */