AtCoder Regular Contest 130 C Digit Sum Minimization

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分类讨论,但是写起来挺答辩的。

首先发现我们要使进位尽量多。

特判怎么重排都没有进位的情况(\\(a_i + b_i < 10\\))。然后枚举个位选的两个数字,并且要求它们和 \\(\\ge 10\\)

  • 如果当前位两个位都有数字,那么从小到大枚举数位的和 \\(\\in [9, 18]\\);如果有数字加起来等于枚举的和就直接进入下一位。注意要优先选非 \\(9\\) 的数,这样留给后面只有一位有数字的进位就更多。如果当前位不可能产生进位了,那么就直接摆烂,随便选。
  • 如果当前位只有一位有数字,优先选 \\(9\\),然后再选其他的(其实不需要)。

然后就做完了。

code
// Problem: C - Digit Sum Minimization
// Contest: AtCoder - AtCoder Regular Contest 130
// URL: https://atcoder.jp/contests/arc130/tasks/arc130_c
// Memory Limit: 1024 MB
// Time Limit: 2000 ms
// 
// Powered by CP Editor (https://cpeditor.org)

#include <bits/stdc++.h>
#define pb emplace_back
#define fst first
#define scd second
#define mems(a, x) memset((a), (x), sizeof(a))

using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef double db;
typedef long double ldb;
typedef pair<ll, ll> pii;

const int maxn = 100100;

int n, m, ca[15], cb[15], cc[15], cd[15];
char a[maxn], b[maxn], c[maxn], s[maxn], t[maxn], ss[maxn], tt[maxn];

void solve() 
	scanf("%s%s", a + 1, b + 1);
	n = strlen(a + 1);
	m = strlen(b + 1);
	bool flag = 0;
	if (n < m) 
		swap(n, m);
		swap(a, b);
		flag = 1;
	
	if (m < n) 
		for (int i = 1; i <= n - m; ++i) 
			c[i] = \'0\';
		
		for (int i = n - m + 1, j = 1; i <= n; ++i) 
			c[i] = b[j++];
		
		for (int i = 1; i <= n; ++i) 
			b[i] = c[i];
		
	
	// printf("%s %s\\n", a + 1, b + 1);
	for (int i = 1; i <= n; ++i) 
		++ca[a[i] - \'0\'];
	
	for (int i = 1; i <= n; ++i) 
		++cb[b[i] - \'0\'];
	
	bool flg = 1;
	for (int i = 1; i <= 9; ++i) 
		for (int j = 1; j <= 9; ++j) 
			if (i + j >= 10 && ca[i] && cb[j]) 
				flg = 0;
				break;
			
		
		if (!flg) 
			break;
		
	
	if (flg) 
		memcpy(ss, a, sizeof(a));
		memcpy(tt, b, sizeof(b));
		if (flag) 
			for (int i = n - m + 1; i <= n; ++i) 
				putchar(tt[i]);
			
			putchar(\'\\n\');
			for (int i = 1; i <= n; ++i) 
				putchar(ss[i]);
			
		 else 
			for (int i = 1; i <= n; ++i) 
				putchar(ss[i]);
			
			putchar(\'\\n\');
			for (int i = n - m + 1; i <= n; ++i) 
				putchar(tt[i]);
			
		
		return;
	
	for (int i = 0; i <= 10; ++i) 
		cc[i] = ca[i];
		cd[i] = cb[i];
	
	int mxk = -1;
	for (s[n] = \'1\'; s[n] <= \'9\'; ++s[n]) 
		for (t[n] = \'1\'; t[n] <= \'9\'; ++t[n]) 
			for (int i = 0; i <= 10; ++i) 
				ca[i] = cc[i];
				cb[i] = cd[i];
			
			if (!ca[s[n] - \'0\'] || !cb[t[n] - \'0\']) 
				continue;
			
			--ca[s[n] - \'0\'];
			--cb[t[n] - \'0\'];
			int xx = s[n] - \'0\', yy = t[n] - \'0\';
			if (xx + yy < 10) 
				continue;
			
			int k = 1;
			for (int i = n - 1; i; --i) 
				if (b[i] == \'0\') 
					if (ca[9]) 
						--ca[9];
						s[i] = \'9\';
						++k;
					 else 
						for (int x = 1; x <= 9; ++x) 
							if (ca[x]) 
								--ca[x];
								s[i] = \'0\' + x;
								break;
							
						
					
					continue;
				
				bool fl = 0;
				for (int o = 9; o <= 18; ++o) 
					for (int p = 1; p < o; ++p) 
						int q = o - p;
						if (1 <= p && p < 9 && 1 <= q && q < 9) 
							if (ca[p] && cb[q]) 
								s[i] = \'0\' + p;
								t[i] = \'0\' + q;
								--ca[p];
								--cb[q];
								fl = 1;
								break;
							 else if (cb[p] && ca[q]) 
								--cb[p];
								--ca[q];
								s[i] = \'0\' + q;
								t[i] = \'0\' + p;
								fl = 1;
								break;
							
						
					
					if (fl) 
						++k;
						break;
					
					for (int p = 1; p < o; ++p) 
						int q = o - p;
						if ((p == 9 && 1 <= q && q <= 9) || (q == 9 && 1 <= p && p <= 9)) 
							if (ca[p] && cb[q]) 
								s[i] = \'0\' + p;
								t[i] = \'0\' + q;
								--ca[p];
								--cb[q];
								fl = 1;
								break;
							 else if (cb[p] && ca[q]) 
								--cb[p];
								--ca[q];
								s[i] = \'0\' + q;
								t[i] = \'0\' + p;
								fl = 1;
								break;
							
						
					
					if (fl) 
						++k;
						break;
					
				
				if (!fl) 
					for (int o = 2; o < 9; ++o) 
						for (int p = 1; p < o; ++p) 
							int q = o - p;
							if (1 <= p && p <= 9 && 1 <= q && q <= 9) 
								if (ca[p] && cb[q]) 
									s[i] = \'0\' + p;
									t[i] = \'0\' + q;
									--ca[p];
									--cb[q];
									fl = 1;
									break;
								 else if (cb[p] && ca[q]) 
									--cb[p];
									--ca[q];
									s[i] = \'0\' + q;
									t[i] = \'0\' + p;
									fl = 1;
									break;
								
							
						
						if (fl) 
							break;
						
					
				
			
			if (k > mxk) 
				mxk = k;
				memcpy(ss, s, sizeof(s));
				memcpy(tt, t, sizeof(t));
			
		
	
	if (flag) 
		for (int i = n - m + 1; i <= n; ++i) 
			putchar(tt[i]);
		
		putchar(\'\\n\');
		for (int i = 1; i <= n; ++i) 
			putchar(ss[i]);
		
	 else 
		for (int i = 1; i <= n; ++i) 
			putchar(ss[i]);
		
		putchar(\'\\n\');
		for (int i = n - m + 1; i <= n; ++i) 
			putchar(tt[i]);
		
	


int main() 
	int T = 1;
	// scanf("%d", &T);
	while (T--) 
		solve();
	
	return 0;


Donation---AtCoder - AtCoder Regular Contest 098

Donation


input1:

4 5
3 1
1 2
4 1
6 2
1 2
2 3
2 4
1 4
3 4


input2:

5 8
6 4
15 13
15 19
15 1
20 7
1 3
1 4
1 5
2 3
2 4
2 5
3 5
4 5

output2:

44

input3:

9 10
131 2
98 79
242 32
231 38
382 82
224 22
140 88
209 70
164 64
6 8
1 6
1 4
1 3
4 7
4 9
3 7
3 9
5 9
2 5

output3:

582

有n个点m条边,每一个点有两个属性,在这个点上的时候要至少有A元,然后要在这个点上支付B元,可以选择在任意时候支付
求最少要携带多少元,才能够将所有的点都支付一遍

int head[maxn];
int n,m,cnt,tot;
ll a[maxn],b[maxn],c[maxn],id[maxn];
int fa[maxn];
int lson[maxn],rson[maxn];
struct node{
	int v,nex;
}e[maxn];
void addEdge(int u,int v){
	e[cnt].v = v;
	e[cnt].nex = head[u];
	head[u] = cnt ++;
}
void init(){
	for(int i=0;i<maxn;i++) fa[i] = i,head[i] = -1;
	cnt = 0;
	tot = 0;
}
bool cmp(int x,int y){
	return a[x] < a[y];
}
int find(int x){
	if(x == fa[x]) return x;
	else return fa[x] = find(fa[x]);
}
void add(int u,int v){
	int fau = find(u);
	int fav = find(v);
	if(fau == fav) return ;
	tot ++;
	u = fau;
	v = fav;
	lson[tot] = u;
	rson[tot] = v;
	a[tot] = max(a[u],a[v]);
	b[tot] = b[u] + b[v];///cost cal
	fa[u] = tot;
	fa[v] = tot;
	fa[tot] = tot;
}
ll dp[maxn];
void dfs(int u){
	if(lson[u]){
		dfs(lson[u]);
		dfs(rson[u]);
	}else dp[u] = a[u];
	dp[u] = min(
	max(a[u]-b[lson[u]],dp[lson[u]]),
	max(a[u]-b[rson[u]],dp[rson[u]])
	);
}
int main()
{
	init();
	n = read,m = read;
	for(int i=1;i<=n;i++) a[i] = read,b[i] = read;
	for(int i=1;i<=n;i++) a[i] = max(a[i] - b[i], 0LL),id[i] = i;
	sort(id+1,id+1+n,cmp);
	for(int i=1;i<=m;i++){
		int u = read,v = read;
		addEdge(u,v);
		addEdge(v,u);
	}
	/*for(int i=1;i<=n;i++){
		cout<<id[i]<<' ';
	}
	puts("");*/
	tot = n;
	// puts("ok");
	for(int i=1;i<=n;i++){
		int u = id[i];
		for(int j = head[u]; ~j; j = e[j].nex){
			int to = e[j].v;
			if(a[to] <= a[u]) add(u,to);
		}
	}
	dfs(tot);
	cout << dp[tot] + b[tot] <<endl;
    return 0;
}

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