feat: 添加多个算法题目解决方案

添加P5542.cpp、P1115.cpp、P6100.cpp和P4188.cpp的解决方案
更新P2258.cpp的实现，增加矩阵处理逻辑

src/11/11/P1115.cpp

@@ -0,0 +1,19 @@
+#include <algorithm>
+#include <cstdint>
+#include <iostream>
+using ll = int64_t;
+
+const ll inf=1e9+7;
+ll n;
+
+int main(){
+    std::cin>>n;
+    ll max=-inf,nmax=-inf;
+    for(ll i=1;i<=n;i++){
+        ll tmp;
+        std::cin>>tmp;
+        nmax=std::max(tmp,nmax+tmp);
+        max=std::max(max,nmax);
+    }
+    std::cout<<max<<"\n";
+}

src/11/11/P4188.cpp

@@ -0,0 +1,84 @@
+#include <iostream>
+#include <vector>
+#include <algorithm>
+using namespace std;
+
+const int MAXN = 100010;
+
+struct Event {
+    int time;
+    int id;
+    bool isStart;
+    
+    bool operator<(const Event& other) const {
+        if (time != other.time) return time < other.time;
+        return isStart > other.isStart; // 结束事件优先处理
+    }
+};
+
+int main() {
+    ios_base::sync_with_stdio(false);
+    cin.tie(nullptr);
+    
+    int n;
+    cin >> n;
+    
+    vector<pair<int, int>> intervals(n);
+    vector<Event> events;
+    
+    for (int i = 0; i < n; i++) {
+        int start, end;
+        cin >> start >> end;
+        intervals[i] = {start, end};
+        events.push_back({start, i, true});
+        events.push_back({end, i, false});
+    }
+    
+    sort(events.begin(), events.end());
+    
+    // 计算总覆盖时间和每个救生员的单独贡献
+    int totalCover = 0;
+    vector<int> aloneTime(n, 0);
+    
+    int activeCount = 0;
+    int lastTime = 0;
+    int singleActive = -1; // 当只有一个救生员活跃时，记录其ID
+    
+    for (const Event& e : events) {
+        if (activeCount > 0) {
+            totalCover += e.time - lastTime;
+        }
+        
+        if (activeCount == 1) {
+            // 只有一个救生员活跃时，这段时间完全属于这个救生员
+            aloneTime[singleActive] += e.time - lastTime;
+        }
+        
+        if (e.isStart) {
+            activeCount++;
+        } else {
+            activeCount--;
+        }
+        
+        // 更新singleActive
+        if (activeCount == 1) {
+            // 找到当前活跃的救生员
+            singleActive = e.id;
+        } else {
+            singleActive = -1;
+        }
+        
+        lastTime = e.time;
+    }
+    
+    // 找到aloneTime的最小值
+    int minAlone = 1e9;
+    for (int i = 0; i < n; i++) {
+        minAlone = min(minAlone, aloneTime[i]);
+    }
+    
+    // 结果是总覆盖时间减去最小的单独贡献
+    int result = totalCover - minAlone;
+    cout << result << endl;
+    
+}

src/11/11/P5542.cpp

@@ -0,0 +1,3 @@
+int main(){
+    
+}

src/11/11/P6100.cpp

@@ -0,0 +1,50 @@
+#include <algorithm>
+#include <cstdint>
+#include <cstdio>
+#include <iostream>
+#include <istream>
+using ll = int64_t;
+
+const ll maxn = 205, inf=1e9+7;
+ll n,k,pre[maxn][maxn],dp[maxn][maxn],ans=-inf,ud[maxn][maxn][maxn];
+
+int main(){
+    std::iostream::sync_with_stdio(false);
+    std::cin.tie(nullptr);
+
+    std::cin>>n>>k;
+    for(ll i=1;i<=n;i++){
+        ll x1,y1,x2,y2;
+        std::cin>>x1>>y1>>x2>>y2;
+        pre[x1][y1]++,pre[x2+1][y2+1]++;
+        pre[x2+1][y1]--,pre[x1][y2+1]--;
+    }
+    for(ll i=1;i<maxn;i++){
+        for(ll j=1;j<maxn;j++){
+            dp[i][j]=dp[i-1][j]+dp[i][j-1]-dp[i-1][j-1]+pre[i][j];
+        }
+    }
+    for(ll l=1;l<maxn;l++){
+        for(ll u=1;u<maxn-1;u++){
+            for(ll d=u;d<maxn;d++){
+                ud[l][u][d]=ud[l][u][d-1]+dp[d][l];
+            }
+        }
+    }
+    // for(ll i=1;i<=10;i++){
+    //     for(ll j=1;j<=10;j++){
+    //         printf("%lld ",ud[j][i][i+1]);
+    //     }
+    //     printf("\n");
+    // }
+    for(ll u=1;u<maxn-1;u++){
+        for(ll d=u;d<maxn;d++){
+            ll nmax=-inf;
+            for(ll i=1;i<maxn;i++){
+                nmax=std::max(ud[i][u][d],nmax+ud[i][u][d]);
+                ans=std::max(ans,nmax);
+            }
+        }
+    }
+    std::cout<<ans<<"\n";
+}

src/11/9/P2258.cpp

@@ -1,3 +1,56 @@
-int main(){
+#include <cstdint>
+#include <cstdio>
+#include <cstdlib>
+#include <iostream>
+#include <istream>
+using ll = int64_t;
+#define sl static inline
+const ll maxn = 18;
+ll n,m,r,c;
+ll a[maxn][maxn],dp[maxn][maxn],h[maxn],ans=1e9+7,lr[maxn][maxn],ud[maxn];
+
+sl void solve(){
+    printf("h[]= ");
+    for(ll i=1;i<=r;i++){
+        printf("%lld ",h[i]);
+    }
+    printf("\n");
+    for(ll l=1;l<m;l++){
+        for(ll l2=l+1;l2<=m;l2++){
+            for(ll i=1;i<=r;i++){
+                lr[l][l2]+=std::abs(a[h[i]][l]-a[h[i]][l2]);
+            }
+        }
+    }
+    for(ll l=1;l<=m;l++){
+        for(ll i=2;i<=r;i++){
+            ud[l]+=std::abs(a[h[i-1]][l]-a[h[i]][l]);
+        }
+    }
     
+}
+sl void dfs(ll start,ll depth){
+    // printf("dfs start%lld, depth=%lld\n",start,depth);
+    if(depth>r){
+        solve();
+        return;
+    }
+    for(ll i=start;i<=n-(r-depth);i++){
+        h[depth]=i;
+        dfs(i+1,depth+1);
+    }
+}
+
+int main(){
+    std::iostream::sync_with_stdio(false);
+    std::cin.tie(nullptr);
+
+    std::cin>>n>>m>>r>>c;
+    for(ll i=1;i<=n;i++){
+        for(ll j=1;j<=m;j++){
+            std::cin>>a[i][j];
+        }
+    }
+    dfs(1, 1);
+
 }