update

README.md

@@ -36,4 +36,12 @@ void bfs(){
         set_color(i, 1);
         vis[i]=true; // 注意初始化错误
         while(!q.empty()){
+```
+
+### [P3957](https://www.luogu.com.cn/problem/P3957)
+#### 初始状态依赖已走过的部分时注意起始点状态
+```cpp
+    for(ll coin{0};coin<=(points[n].posit-d);++coin){
+        for(ll i{0};i<max_n;i++)dp[i]=ll_min;
+        dp[0]=0; // 注意第0个点是能到达的reachable
 ```

src/P1330/P1330.cpp

@@ -4,7 +4,6 @@
 #include <algorithm>
 
 using ll = long long;
-using std::endl;
 static auto &is = std::cin;
 static auto &os = std::cout;
 

src/P3957/P3957.cpp

@@ -1,17 +1,53 @@
+#include <cstring>
 #include <iostream>
-#include <bitset>
+#include <algorithm>
+#include <limits>
+#include <type_traits>
 
-using ll = unsigned long long;
+using ll = long long;
 
 auto &is = std::cin;
 auto &os = std::cout;
 
-const ll /*max_n = 5e5+5*/max_n = 500+5, max_d = 2e3+5, max_x = 1e9+5, max_k = 1e9+5;
+const ll max_n = 5e5+5, ll_min{std::numeric_limits<decltype(ll_min)>::min()};
+ll n, d, k;
+struct Point{
+    ll posit,score;
+}points[max_n];
+ll dp[max_n];
 
-ll n,d,k;
-std::bitset<max_n> dp[max_d][max_n][max_n];
+void flush_exit(){
+    os<<std::flush;
+    _Exit(0);
+}
 
 int main(){
     is>>n>>d>>k;
-    
+    for(ll i{1};i<=n;++i){
+        is>>points[i].posit>>points[i].score;
+    }
+
+    for(ll coin{0};coin<=(points[n].posit-d);++coin){
+        for(ll i{0};i<max_n;i++)dp[i]=ll_min;
+        dp[0]=0; // 注意第0个点是能到达的reachable
+        const ll max_step {coin+d}, min_step {std::max((ll)1,d-coin)};
+        for(ll i{1};i<=n;++i){
+            for(ll from{i-1};from>=0;from--){
+                ll dis{points[i].posit-points[from].posit};
+                if(min_step<=dis){
+                    if(dis<=max_step){
+                        if(dp[from]==ll_min)continue;
+                        dp[i] = std::max(dp[i],dp[from]+points[i].score);
+                        if(dp[i]>=k){
+                            os<<coin<<'\n';
+                            flush_exit();
+                        }
+                    }else{
+                        break;
+                    }
+                }
+            }
+        }
+    }
+    os<<-1<<'\n';
 }