update

src/B2104/B2104.cpp

@@ -0,0 +1,30 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+using ll = int64_t;
+
+const ll maxn{105};
+ll n,m;
+ll a[maxn][maxn];
+
+int main(){
+    iostream::sync_with_stdio(false),cin.tie(0),cout.tie(0);
+    cin>>n>>m;
+    const auto ra = [&](){
+        ll t;
+        for(ll i{1};i<=n;i++){
+            for(ll j{1};j<=m;j++){
+                cin>>t;
+                a[i][j]+=t;
+            }
+        }
+    };
+    ra();
+    ra();
+    for(ll i{1};i<=n;i++){
+        for(ll j{1};j<=m;j++){
+            cout<<a[i][j]<<' ';
+        }
+        cout<<'\n';
+    }
+}   

src/B2105/B2105.cpp

@@ -0,0 +1,55 @@
+#include <bits/stdc++.h>
+using ll = int64_t;
+using namespace std;
+
+const ll maxn{ll(100+5)};
+ll n,m,k,a[maxn][maxn],b[maxn][maxn],c[maxn][maxn];
+
+struct CinN{
+    char c;
+    ll n,w;
+    CinN &operator>>(ll &num)noexcept{
+        c=n=0;
+        w=1;
+        while(!isdigit(c)){
+            if(c=='-')w=-1;
+            c=getchar();
+        }
+        while(isdigit(c)){
+            n=n*10+c-'0';
+            c=getchar();
+        }
+        num=n*w;
+        return *this;
+    }
+}cinn;
+
+#define cin cinn
+
+int main(){
+    iostream::sync_with_stdio(0)/*,cin.tie(0),cout.tie(0)*/;
+    cin>>n>>m>>k;
+    const auto rdmtx = [](ll (&mtx)[maxn][maxn],ll const &n,ll const &m){
+        for(ll i{1};i<=n;i++){
+            for(ll j{1};j<=m;j++){
+                cin>>mtx[i][j];
+            }
+        }
+    };
+    const auto pmtx = [](ll (&mtx)[maxn][maxn],ll const &n,ll const &m){
+        for(ll i{1};i<=n;i++){
+            for(ll j{1};j<=m;j++){
+                cout<<mtx[i][j]<<' ';
+            }
+            cout<<'\n';
+        }
+    };
+    rdmtx(a,n,m);
+    rdmtx(b,m,k);
+    for(ll l{1};l<=k;l++)
+        for(ll i{1};i<=n;i++)
+            for(ll j{1};j<=m;j++){
+                c[i][l]+=a[i][j]*b[j][l];
+            }
+    pmtx(c,n,k);
+}