題目可以去pta教育超市找
寫第一題還很清醒。（耗時15分鐘）
#include<bits/stdc++.h>
using namespace std;
string s;
int sum = 0,len = 0;
int cnt = 0;
int check(char c){
if(c >= 'a' && c <= 'z'){
return 1;
}else if(c <= 'Z' && c >= 'A'){
return 2;
}else if(c <= '9' && c >= '0'){
return 3;
}else{
return 0;
}
}
void f(string t){
len += t.size();
if(t.size()){
cnt ++;
}
bool f1 = false, f2 = false, f3 = false;
for(int i = 0;i < t.size();i ++){
if(check(t[i]) == 1){
f1 = true;
}else if(check(t[i]) == 2){
f2 = true;
}else{
f3 = true;
}
}
if(f1 && f2 && f3){
sum += 5;
}else if((f1 && f3) || (f2 && f3)){
sum += 3;
}else if(f1 && f2){
sum += 1;
}
}
void solve(){
while(cin >> s){
string t = "";
for(int i = 0;i < s.size();i ++){
if(check(s[i])){
t += s[i];
}else{
f(t);
t = "";
}
}
if(t.size()){
f(t);
}
}
cout << sum << endl << len << ' ' << cnt << endl;
}
int main(){
int t = 1;
while(t --){
solve();
}
}
第二題就開始犯迷糊了，題面太噁心了，val陣列少寫了一個半天沒找到，無語了。。。（耗時25分鐘）
#include<bits/stdc++.h>
using namespace std;
int val[] = {0, 25, 21, 18, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0};
struct d{
int first;
int second;
}a[40];
bool cmp(d x, d y){
if(x.first != y.first){
return x.first > y.first;
}else{
return x.second < y.second;
}
}
void solve(){
int n;
cin >> n;
map<int,int>mp;
while(n --){
for(int i = 0;i < 20;i ++){
int x, y;
cin >> x >> y;
mp[x] = 1;
a[x] = {a[x].first + val[y], x};
}
}
sort(a + 1, a + 31, cmp);
for(int i = 1;i <= 30;i ++){
if(mp[a[i].second])
cout << a[i].second << ' ' << a[i].first << endl;
}
}
int main(){
int t = 1;
while(t --){
solve();
}
}
第三題，一開始忘了如何dfs求排列，求完排列果斷暴力，最後就14分，當時想的是dp，沒想到就是一個簡單數學問題。每個數可以拆個十百千來算，就是個排序
#include<bits/stdc++.h>
using namespace std;
int a[5], st[5];
map<int,int>mp;
int n;
vector<int>b;
set<int>s;
vector<int>ans;
void dfs1(int val, int cnt){
if(cnt >= n){
s.insert(val);
return;
}
for(int i = 1;i <= n;i ++){
if(!st[i]){
st[i] = 1;
dfs1(val * 10 + a[i], cnt + 1);
st[i] = 0;
}
}
}
void solve(){
cin >> n;
for(int i = 1;i <= n;i ++){
cin >> a[i];
}
dfs1(0, 0);
long long sum = 0;
for(auto x : s){
b.push_back(x);
sum += x * x;
}
int f = 1;
for(int i = 0;i < b.size();i += 2){
int c = b[i], d = b[i + 1];
if(f == 1)
cout << c << endl;
else
cout << d << endl;
f *= -1;
}
}
int main(){
int t = 1;
while(t --){
solve();
}
}
第四題，當時寫最短路，然後寫的很對就是過不去，最後沒辦法，只能二分答案，
#include<bits/stdc++.h>
using namespace std;
#define pii pair<int,int>
int n, m, s, t;
vector<pair<int,int>>e[1010];
int val[1010], st[1010], dist[1010], pre[1010];
bool dij(int mid){
priority_queue<pii, vector<pii>, greater<pii>>q;
memset(pre, -1, sizeof pre);
memset(st, 0, sizeof st);
memset(dist, 0x3f, sizeof dist);
q.push({0, s});
while(q.size()){
auto k = q.top();
q.pop();
int d = k.first;
int id = k.second;
if(st[id]){
continue;
}
st[id] = 1;
for(auto [x, y] : e[id]){
if(val[x] > mid && x != t){
continue;
}else{
if(y + d < dist[x]){
dist[x] = y + d;
q.push({dist[x], x});
}
}
}
}
if(dist[t] == 0x3f3f3f3f){
return false;
}
return true;
}
void solve(){
cin >> n >> m;
cin >> s >> t;
int ma = -1, mi = 0x3f3f3f3f;
for(int i = 1;i <= n;i ++){
cin >> val[i];
ma = max(ma, val[i]);
mi = min(mi, val[i]);
}
for(int i = 0;i < m;i ++){
int x, y, z;
cin >> x >> y >> z;
e[x].push_back({y, z});
e[y].push_back({x, z});
}
int l = mi - 1, r = ma + 1;
while(l + 1 != r){
int mid = l + r >> 1;
if(dij(mid)){
r = mid;
} else{
l = mid;
}
}
if(!dij(r)){
cout << "Impossible";
}else{
cout << dist[t] << ' ' << r << endl;
}
}
int main(){
int t = 1;
while(t --){
solve();
}
}
賽後秒出正解，服了啊，錯誤原因是我建邊建錯了
#include<bits/stdc++.h>
using namespace std;
#define pii pair<pair<int,int>,int>
int n, m, s, t;
vector<pair<int,int>>e[1010];
int val[1010], st[1010], dist[1010], pre[1010];
int res[1010];
bool dij(){
priority_queue<pii, vector<pii>, greater<pii>>q;
memset(pre, -1, sizeof pre);
memset(st, 0, sizeof st);
memset(dist, 0x3f, sizeof dist);
q.push({{0, 0}, s});
while(q.size()){
auto k = q.top();
q.pop();
int d = k.first.first;
int v = k.first.second;
int id = k.second;
if(st[id]){
continue;
}
st[id] = 1;
for(auto [x, y] : e[id]){
if(dist[x] > y + d){
dist[x] = y + d;
pre[x] = id;
res[x] = max(v, val[x]);
q.push({{dist[x], res[x]}, x});
}else if(dist[x] == y + d && res[x] > v){
res[x] = max(val[x], v);
pre[x] = id;
q.push({{dist[x], res[x]}, x});
}
}
}
if(dist[t] == 0x3f3f3f3f){
return false;
}
return true;
}
void solve(){
cin >> n >> m;
cin >> s >> t;
for(int i = 1;i <= n;i ++){
cin >> val[i];
}
val[s] = 0;
val[t] = 0;
for(int i = 0;i < m;i ++){
int x, y, z;
cin >> x >> y >> z;
e[x].push_back({y, z});
e[y].push_back({x, z});
}
if(!dij()){
cout << "Impossible";
}else{
cout << dist[t] << ' ' << res[t];
}
}
int main(){
int t = 1;
while(t --){
solve();
}
}
這次比賽很糟糕，但是也學到了不少東西。下次注意