题目链接 https://www.luogu.com.cn/problem/P9561?contestId=126525

想问问为什么以下做法是错误的

大体思路是对线段离散化后求第i段线段为红色对答案的贡献数，其中dp是不同颜色的前缀和数组

ll n, m, h, x, y, z, a, b, c, d, e, u, v, w, i, j, k, l, r, nn, mm, ans, p, q, len, T, he;
ll wcnm = 1, id = 0;
 
struct node {
    ll l, r, c;
}A[N];
 
bool cmp(node a, node b) {
    return a.r < b.r;
}
map<ll, ll>B;
ll dp[N][3];
 
int main() {
    ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
 
    for (cin >> T; T; --T) {
        cin >> n;
        B.clear();
        for (i = 1; i <= n; ++i) {
            cin >> a >> b >> c;
            A[i] = { a,b,2 - c };
            B[a - 1] = B[a] = B[b] = B[b + 1] = 0;
        }
 
        len = 0;
        for (auto& x : B)x.second = ++len;
 
        for (i = 1; i <= n; ++i)A[i].l = B[A[i].l], A[i].r = B[A[i].r];
        sort(A + 1, A + n + 1, cmp);
 
        dp[1][0] = 1;
        j = 1;
 
        for (i = 2; i <= len; ++i) {
            dp[i][0] = dp[i - 1][0];
            dp[i][1] = dp[i - 1][1];
            dp[i][2] = dp[i - 1][2];
 
            while (j <= n && i == A[j].r) {
                l = A[j].l, r = A[j].r, c = A[j].c;
                d = dp[l - 1][0] + dp[i][c] - dp[l - 1][c];
                dp[i][c] += d;
                dp[i][0] += d;
                ++j;
            }
        }
 
        cout << dp[len][0] << endl;
    }
}