链接:
https://vjudge.net/problem/Gym-100741A
题意:
Mathematicians are interesting (sometimes, I would say, even crazy) people. For example, my friend, a mathematician, thinks that it is very fun to play with a sequence of integer numbers. He writes the sequence in a row. If he wants he increases one number of the sequence, sometimes it is more interesting to decrease it (do you know why?..) And he likes to add the numbers in the interval [l;r]. But showing that he is really cool he adds only numbers which are equal some mod (modulo m).
Guess what he asked me, when he knew that I am a programmer? Yep, indeed, he asked me to write a program which could process these queries (n is the length of the sequence):
p r It increases the number with index p by r. (, )
You have to output the number after the increase.p r It decreases the number with index p by r. (, ) You must not decrease the number if it would become negative.
You have to output the number after the decrease.
s l r mod You have to output the sum of numbers in the interval which are equal mod (modulo m). () ()
思路:
看半天没看懂题.
建10个树状数组即可, 对模m的每种情况分别统计.
代码:
#include <iostream>
#include <cstdio>
#include <cstring>
#include <vector>
//#include <memory.h>
#include <queue>
#include <set>
#include <map>
#include <algorithm>
#include <math.h>
#include <stack>
#include <string>
#include <assert.h>
#include <iomanip>
#define MINF 0x3f3f3f3f
using namespace std;
typedef long long LL;
const int INF = 1e9;
const int MAXN = 1e4+10;
LL A[MAXN], C[15][MAXN];
int n, m, q;
int Lowbit(int x)
{
return x&(-x);
}
void Add(int pos, int mod, LL val)
{
while (pos <= n)
{
C[mod][pos] += val;
pos += Lowbit(pos);
}
}
LL Query(int pos, int mod)
{
LL ans = 0;
while (pos > 0)
{
ans += C[mod][pos];
pos -= Lowbit(pos);
}
return ans;
}
int main()
{
scanf("%d%d", &n, &m);
for (int i = 1;i <= n;i++)
{
scanf("%lld", &A[i]);
Add(i, A[i]%m, A[i]);
}
scanf("%d", &q);
char opt[5];
int l, r, mod;
while (q--)
{
scanf("%s", opt);
if (opt[0] == 's')
{
scanf("%d%d%d", &l, &r, &mod);
printf("%lld\n", Query(r, mod)-Query(l-1, mod));
}
else if (opt[0] == '+')
{
scanf("%d%d", &l, &r);
Add(l, A[l]%m, -A[l]);
A[l] += r;
Add(l, A[l]%m, A[l]);
printf("%lld\n", A[l]);
}
else
{
scanf("%d%d", &l, &r);
Add(l, A[l]%m, -A[l]);
if (r <= A[l])
A[l] -= r;
Add(l, A[l]%m, A[l]);
printf("%lld\n", A[l]);
}
}
return 0;
}