feat: 添加三个算法题目解决方案

添加了三个算法题目的解决方案文件：
1. P3951.cpp - 实现简单的数学计算
2. P14362.cpp - 基础IO优化设置
3. P3952.cpp - 实现复杂度分析器，判断代码块的时间复杂度

src/11/4/P14362.cpp

@@ -0,0 +1,13 @@
+#include <cstdint>
+#include <iostream>
+#include <istream>
+using ll = int64_t;
+
+
+
+int main(){
+    std::iostream::sync_with_stdio(false);
+    std::cin.tie(nullptr);
+
+    
+}

src/11/4/P3951.cpp

@@ -0,0 +1,6 @@
+#include <iostream>
+int main(){
+    int a,b;
+    std::cin>>a>>b;
+    std::cout<<(a*b)-a-b<<"\n";
+}

src/11/4/P3952.cpp

@@ -0,0 +1,100 @@
+#include <algorithm>
+#include <cctype>
+#include <cstddef>
+#include <cstdint>
+#include <cstdio>
+#include <cstdlib>
+#include <deque>
+#include <iostream>
+#include <istream>
+#include <set>
+#include <string>
+using ll = int64_t;
+#define sl static inline
+
+ll n,op,res,now,nres;
+char tmp;
+std::string st;
+std::set<char> used;
+bool iserror;
+struct S{
+    char c;
+    ll res;
+    bool isok;
+};
+std::deque<S> stk;
+#define printf
+sl void solve(){
+    op=0,res=0;
+    iserror=false;
+    used.clear();
+    stk.clear();
+    std::cin>>tmp>>tmp>>tmp;
+    if(tmp=='1'){
+        op=0;
+        std::cin>>tmp;
+    }else{
+        std::cin>>tmp;
+        std::cin>>op;
+        std::cin>>tmp;
+    }
+    printf("STARTING %lld Get O(n^%lld)\n",++now,op);
+    while(std::cin>>st){
+        printf("while st=%s\n",st.data());
+        ll add=0;
+        if(st=="F"){
+            char i;
+            bool isok=(stk.size()?stk.back().isok:true);
+            std::string x,y;
+            std::cin>>i>>x>>y;
+            if(y=="n"&&x!="n"){
+                add++;
+            }else if(x=="n"&&isdigit(y[0])){
+                isok=false;
+            }else if(isdigit(x[0])&&isdigit(y[0])){
+                ll nx=atoi(x.data()),ny=atoi(y.data());
+                if(nx>ny){
+                    isok=false;
+                }
+            }
+            if(used.find(i)!=used.end()){
+                iserror=true;
+            }else{
+                used.emplace(i);
+            }
+            stk.push_back({i,stk.empty()?add:stk.back().res+add,isok});
+        }else if(st=="E"){
+            if(stk.empty()){
+                iserror=true;
+            }else{
+                printf("pop stk c=%c, res=%lld\n",stk.back().c,stk.back().res);
+                if(stk.back().isok){
+                    res=std::max(res,stk.back().res);
+                }
+                used.erase(stk.back().c);
+                stk.pop_back();
+            }
+        }else{
+            n=atoi(st.data());
+            break;
+        }
+    }
+    if(stk.size())iserror=true;
+    if(iserror){
+        std::cout<<"ERR\n";
+    }else{
+        std::cout<<(res==op?"Yes":"No")<<"\n";
+    }
+}
+
+int main(){
+    std::iostream::sync_with_stdio(false);
+    std::cin.tie(nullptr);
+
+    ll t;
+    std::cin>>t;
+    std::cin>>n;
+    while(t--){
+        solve();
+    }
+}