48 lines
1.1 KiB
C++
48 lines
1.1 KiB
C++
#include <bits/stdc++.h>
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using namespace std;
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const int N = 5e5 + 10;
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int a[N]; // a是原数组。c是差分数组，用树状数组维护
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int n, m;
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// 树状数组模板
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typedef long long LL;
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#define lowbit(x) (x & -x)
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int c[N];
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void add(int x, int d) {
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for (int i = x; i < N; i += lowbit(i)) c[i] += d;
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}
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LL sum(int x) {
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LL res = 0;
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for (int i = x; i; i -= lowbit(i)) res += c[i];
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return res;
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}
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int main() {
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#ifndef ONLINE_JUDGE
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freopen("P3368.in", "r", stdin);
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#endif
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scanf("%d %d", &n, &m);
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// 原数组
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for (int i = 1; i <= n; i++) scanf("%d", &a[i]);
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// 保存差分数组
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for (int i = 1; i <= n; i++) add(i, a[i] - a[i - 1]);
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int op, l, r, v, k;
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while (m--) {
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scanf("%d", &op);
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if (op == 1) {
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scanf("%d %d %d", &l, &r, &v);
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add(l, v), add(r + 1, -v);
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} else {
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scanf("%d", &k);
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// 树状数组维护的是变化量，还需要加上原来的值
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printf("%d\n", sum(k)); // 求某点的值
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}
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}
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return 0;
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}
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